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TABLE OF CONTENTS

SALTCEDAR

Acknowledgements

Foundational Funders

Content

Special Thanks

Ordering Information

INTRODUCTION

Preventing the Introduction

and Spread of Invasive Species

Controlling Invasive Plants

Plant Reproductive Strategies

Seed Bank

Plant Life Cycles

Control Methods

Species Prevalence

Habitat Preferences

Prohibited Noxious Weed

Noxious Weed

Weed Inspectors

QUICK ID GUIDE

Yellow Flowers

White Flowers

Red/Purple/Pink Flowers

Green Flowers

Blue/Orange Flowers

Burdocks

Hawkweeds

Knapweeds

Thistles

INVASIVE PLANTS

Plant Diagrams

Absinthe Wormwood

African Rue

Alkali Swainsonpea

Amaranth, Palmer

Autumn Olive

Baby’s Breath, Common

Balsam, Himalayan

Barberry, Common

Bartsia, Red

Bellflower, Creeping

Bindweed, Field

Blueweed

Brome, Downy

Brome, Japanese

Buckthorn, Common

Burdock, Great

Burdock, Lesser

Burdock, Woolly

Buttercup, Tall

Chamomile, Scentless

Chicory

Cicer Milkvetch

Cinquefoil, Sulphur

Clematis, Yellow

Cockle, White

Crupina, Common

Daisy, Ox-eye

Dame’s Rocket

Dyer’s Woad

Eurasian Water Milfoil

Flowering Rush

Garlic Mustard

Goatgrass, Jointed

Hawkweed, Common

Hawkweed, European

Hawkweed, Kingdevil

Hawkweed, Meadow

Hawkweed, Mouse-Ear

Hawkweed, Orange

Hawkweed, Polar

Hawkweed, Queendevil

Hawkweed, Smooth

Hawkweed, Spotted

Hawkweed, Tall

Hawkweed, Wall

Hawkweed, Whiplash

100

Hawkweed, Yellowdevil

101

Henbane, Black

102

Hoary Alyssum

103

Hoary Cress

105

Hogweed, Giant

106

Hound’s Tongue

107

Iris, Pale Yellow

108

Jimsonweed

109

Knapweed, Bighead

110

Knapweed, Black

111

Knapweed, Brown

113

Knapweed, Diffuse

114

Knapweed, Hybrid

115

Knapweed, Meadow

116

Knapweed, Russian

117

Knapweed, Spotted

118

Knapweed, Squarrose

119

Knapweed, Tyrol

120

Knotweed, Giant

121

Knotweed, Himalayan

122

Knotweed, Hybrid

123

Knotweed, Japanese

125

Kochia

126

Loosestrife, Purple

127

Medusahead

128

Mullein, Common

129

Nutsedge, Yellow

130

Pepper-Grass, Broad-

Leaved

131

Persian Darnel

132

Phragmities, Invasive

133

Puncturevine

134

Queen Anne’s Lace

135

Ragwort, Tansy

136

Rush Skeletonweed

137

Russian Olive

138

Saltcedar/Tamarisk

139

Saltlover

140

Scabious, Field

141

Sow Thistle, Perennial

142

Spurge, Leafy

143

St John’s-Wort, Common

144

Starthistle, Yellow

145

Swallowwort, Black

146

Swallowwort, Pale/

European

147

Tansy, Common

149

Teasel, Common

149

Teasel, Cut-Leaf

150

Thesium, Field

151

Thistle, Bull

152

Thistle, Canada

153

Thistle, Marsh

154

Thistle, Nodding

155

Thistle, Plumeless

156

Toadflax, Dalmatian

157

Toadflax, Yellow

158

Ventenata

159

Waterhemp, Tall

160

Wild Caraway

161

Wild Parsnip

162

GLOSSARY

165

Thumbnails of Other

Common Weeds

167

Credits

169

Resources/References

ACKNOWLEDGEMENTS

Ron Bartholow was the keen “Weed Man” of Wheatland

County from 2001-2015. His efforts were instrumental in

the production of this book. His passion, wit and knowledge

will be fondly missed by all who knew him. Rest In Peace.

FOUNDATIONAL FUNDERS

We sincerely recognize Wheatland County for developing

the first three editions, which served as the foundation for

all subsequent versions of the guide.

CONTENT



Sarah Schumacher, Ron Bartholow — Wheatland County



Megan Evans, Paige Kuczmarski, Jane Fulton, Madison

Meszaros, Julia Bizon, George Bloom — Alberta Invasive

Species Council

SPECIAL THANKS



Chris Neeser, Alberta Agriculture, Forestry and Rural

Economic Development



Laurie Hamilton, Alberta Native Plant Council



Kelly Cooley, CoolPro Solutions



Nicole Kimmel, Doug Macaulay, Todd Green, Ashley

Tkachyk, Qiting Chen, Natalie LaForest — Alberta

Invasive Species Council Board Directors

ORDERING INFORMATION

Contact communications@abinvasives.ca or visit

abinvasives.ca for details on how to order print copies.

This Guide shall not be sold for profit.

INTRODUCTION

Invasive species such as invasive plants pose a major threat

to Alberta’s economy and environment. This

Invasive Plants

of Alberta

guide is a field-friendly tool to assist with invasive

plant identification through plant descriptions and habitat

information for the 95 provincially regulated invasive plant

species that are listed under the Alberta

Weed Control Act

as well as select others that are currently unregulated but

may require special management.

Invasive species are organisms that originate somewhere

else (i.e., they are exotic) and cause harm in their new

environment. Invasive species have the potential to

dominate ecosystems through their various, often

SPOTTED KNAPWEED

aggressive, life strategies. These species are often well-

adapted to access niches that were previously occupied

by native species; thereby displacing the native species.

Invasive species thrive in new environments because they

are not kept in check by the habitat components that were

present in their original habitat. These components include

predators, parasites, other competitors for resources, soil

and/or climactic conditions, etc. Not all exotic species

become invasive outside of their native range but species

that do can have serious impacts on our environment,

economy, human and animal health.

Invasive species can drastically alter the natural ecosystems

we strive to preserve by competing for limited resources,

displacing native species and creating monocultures that

provide little ecological value. Encroachment on existing

niches by invasive plants can happen via a suite of different

life strategies, such as high and/or rapid reproductive

output, vegetative reproduction, early germination,

allelopathy, etc. For example, there are many examples of

very successful vegetative reproductive strategies found

in invasive plants like purple loosestrife, where new plants

can form vegetatively from a single root fragment, or

like flowering rush, where creeping root systems create

dense colonies. Invasive species can also reduce habitat

and resources for wildlife, increase soil erosion and

sedimentation into water systems and increase wildfire risk.

Once established, invasive plants require a significant

amount of time, labour and money to manage, with some

plants almost impossible to eradicate. Economic impacts

from invasive plants are estimated to cost two billion

dollars per year in Alberta. This includes economic losses

for canola producers, beef cattle industry, crop and grass

yields, and grazing potential for livestock. Although invasive

plant management in the agricultural sector (e.g., pasture/

rangelands, cultivation) accounts for the majority of the

economic costs, other sectors, such as forestry, oil and

gas, municipalities, and conservation managers still incur a

significant expense managing and controlling invasive plants.

Not only can invasive species impact our environment

and economy, they can also harm humans, wildlife and

livestock. Some plants are toxic to humans and livestock

if consumed such as yellow starthistle or St John’s-wort.

Consumption may be less likely for an unfamiliar species;

however, contact through removal or the identification

process may cause injury. For example, the sap of giant

hogweed can cause severe rashes, sensitivity to sunlight,

blisters and even blindness.

LEAFY SPURGE

PREVENTING THE INTRODUCTION

AND SPREAD OF INVASIVE SPECIES

Take action against invasive species in Alberta!

There are many ways to take action to help prevent the

spread of invasive species in the province: Prevention is

the most cost-effective method for avoiding the negative

impacts of invasive species, as many invasive plants are

very difficult to control once established.

WILDFLOWERS NOT WEEDS

Wildflowers are native plants that

originated in Alberta alongside

pollinators, birds, and wildlife,

helping support healthy, resilient

ecosystems.

Weeds, or invasive plants, however, are non-native species

that spread aggressively, displace native vegetation,

reduce biodiversity, and cause significant ecological and

economic harm.

Looks can be deceiving.

Many invasive plants are

colourful and attractive, but

they can quietly crowd out

the diverse native wildflowers

Alberta’s ecosystems

depend on. This loss affects

biodiversity, including the

more than 370 native bee

species that rely on native

plants for food. Not every

pretty flower belongs here.

GROW ME INSTEAD

Make a difference in your

community and commit

to being plantwise! Learn

how to prevent the spread

of invasive plants from

horticultural practices. Avoid pre-packaged wildflower

mixes and choose suitable non-invasive alternatives for

your garden bed or landscape to prevent future spread and

serve to protect and preserve Alberta’s natural environment.

If you do come across an invasive plant, remove it before it

flowers and properly dispose of it in your local landfill – never

compost invasive plants!

PLAY CLEAN GO

Invasive species have many pathways of

spread. For instance, weed seeds can

be easily transferred to the soil from

mud on boots or vehicles, some seeds

even have special hooks to help them

hitch a ride on clothing or pets. By learning

how to inspect and clean your belongings

and knowing the source of items purchased, we

can begin to reduce the chance of inadvertently spreading

species that could harm the areas we cherish. Whether

walking, hiking, climbing, biking or riding your horse, it’s

important to make sure you don’t accidently move invasive

species from place to place. Come clean, leave clean, make

sure to stay on designated trails and before leaving, inspect

your belongings and remove any dirt, plants, seeds or bugs

from yourself, your pets and your equipment.

WEED FREE FORAGE

Contaminated hay or straw is one way invasive plants

are spread across the province, between provinces and

around the world. The Alberta Certified Weed Free Forage

program maintains the North American Invasive Species

Management Association’s international weed free forage

standards which are designed to provide assurance to

all participants that certified forage meets a minimum

acceptable standard and limits the spread of invasive plant

species through contaminated forage.

COMMON BURDOCK

EDDMapS

Early detection and rapid response is

the key to preventing establishment

of invasive species before it is too late.

Report invasive species from the field

using the power of your smartphone!

The EDDMapS (Early Detection and

Distribution Mapping System) app

allows users to identify invasives

species, view local and national distribution maps as well as

track and report invasive species occurrences across Canada!

Reports of invasive species, whether that be a plant, animal

or even a disease, are uploaded, verified and sent to the local

authority for follow-up.

DON’T LET IT LOOSE!

Common aquarium, live food, and

pond species can become invasive

when released into the wild.

Releasing pond water, plants, fish,

or other aquatic species—dead or

alive—is illegal and can result in large

fines or jail time.

Pour aquarium water onto dry land, and freeze plants before

disposing of them in the garbage. Unwanted pets can be

returned to pet stores, rehomed, or donated to schools and

community organizations. After a pet passes, dispose of it in

the garbage or bury it—never flush it.

CLEAN DRAIN DRY

Aquatic invasive species, such

as zebra and quagga mussels

and aquatic plants, can spread

between waterbodies on boats,

watercraft, and equipment that

are not properly cleaned, drained,

and dried.

Clean:

Inspect and remove all plants, mud, and debris from

watercraft, trailers, and gear at the access point. Rinse or

pressure wash with hot water when possible, away from

storm drains and waterways.

Drain:

Empty all water from bait buckets, bilges, ballasts, live

wells, coolers, and internal compartments before leaving the

waterbody.

Dry:

Allow all watercraft and equipment to dry completely

between uses.

CONTROLLING INVASIVE PLANTS

In order to effectively control invasive plant species, it is

important to first understand how the plant reproduces, its

life cycle and identification of plant at each stage in its life

cycle.

Controlling invasive plant species infestations is a

long-term commitment. One season or even several seasons

of control is rarely adequate for many reasons, such as the

plant’s ecology or life strategies.

RUSSIAN KNAPWEED

Plant Reproductive Strategies

Most plants reproduce by seed, or vegetatively through

various plant parts, such as creeping roots or both. Many

plant species are able to reproduce using both strategies.

For plants that reproduce by seed alone, removal of the

flower head and/or seeds is key to controlling it. To control

invasive plants that reproduce vegetatively, removal of all

parts of the plant (seeds, roots, stolons, etc.) is necessary.

Seed Bank

Sites where invasive plant species have been controlled

must be monitored for years to control any new growth.

Invasive plants that have gone to seed drop their seeds

into the soil where the seeds remain as part of the ‘seed

bank’ until the conditions are right for gemination. Some

invasive plant species seeds are viable for only a couple of

years, while others are viable for well over 100 years (e.g.,

common mullein).

FLOWERING RUSH

Plant Life Cycles

ANNUAL

Annual plants complete their entire life cycle, germination,

growth, and reproduction, within a single year, typically

reproducing by seed. They are classified as either summer

or winter annuals.

Winter annuals germinate in the fall, overwinter, and

resume growth in the spring, completing their life cycle

before summer begins (e.g., downy brome). In contrast,

summer annuals germinate in the spring and complete

their life cycle by the end of the same growing season

(e.g., Himalayan balsam).

BIENNIAL

Biennial plants complete their life cycle (germinate, grow,

and reproduce) in two years. Most biennials produce a basal

rosette (circle of leaves emanating from a central point,

typically from a taproot) of leaves in the first year. In the

second year, the plant sends up a flowering stalk, sets seed

and dies. Examples of biennial invasive plant species include

blueweed, common mullein, lesser burdock and black

henbane.

PERENNIAL

Perennials plants live for three or more years and continue

to grow and reproduce year after year. There are both

simple perennials and creeping rooted perennials. Simple

perennials feature tap roots and grow as individual plants

(e.g., dandelion). Creeping rooted perennials feature many

long horizontally oriented underground rhizomes radiating

out from parent plants that are interconnected and capable

of generating multiple new plant shoots (e.g., creeping

bellflower).

Control Methods

There is no single best invasive species control method;

invasive species managers that use a variety of control

options often have the most success. One must consider

the plant method of reproduction, life cycle, life cycle stage

and the location of the invasive plant when implementing

control. Effective control requires the development of

a long-term plan utilizing several control options and

monitoring for regrowth each year.

BIOLOGICAL CONTROL

Biological control, or biocontrol, is a method of introducing

the natural predators of invasive plant species into the

environment where they have become invasive to help

restore ecological balance. Biocontrol does not usually

eradicate the weed, but rather reduces its populations to

manageable levels so that native and desirable vegetation

can re-establish.

Insects are commonly used as biological control or

‘biocontrol’ agents due to their ability to establish and

increase their population on their own once released at

a site, making them a very low maintenance and cost-

effective long-term option. Effective biocontrol agents

die-back once the target plant has been eradicated Robust

studies are conducted on all potential biocontrol agents

prior to being released in Canada to ensure there are no

impacts to non-target species. Therefore, biocontrol is

safe to employ in your own management program. Please

contact your local Agricultural Fieldman or the Alberta

Invasive Species Council to find out how to order a

biocontrol release for your invasive plant infestation.

The use of biocontrol can be effective for many invasive plant

species, especially simple and creeping-rooted perennials,

when used in conjunction with other control methods.

TARGETED GRAZING

Targeted grazing is a strategic tool that uses livestock to

control invasive plants by focusing grazing pressure on

specific species at the right time. By selecting appropriate

animals (e.g., sheep, goats, or cattle) and grazing during

vulnerable growth stages, targeted grazing can reduce

plant vigour, limit flowering, and prevent seed production.

However, it is not effective for all species—some plants

are unpalatable or toxic to livestock, and others may

require different control methods.

It is most effective

when applied intensively and repeatedly over multiple

years, and often works best when combined with other

control methods such as herbicides or mechanical

treatments. While not a quick fix, targeted grazing can be

a cost-effective and environmentally friendly approach

that supports long-term vegetation management and

restoration goals.

MECHANICAL CONTROL

HAND-PULLING/DIGGING

Hand-pulling is very effective in controlling invasive

plants that reproduce only by seed. For creeping rooted

perennials, hand-pulling will remove the seed source, but

regrowth can occur from root fragments that remain in

the soil. Hand-pulling is most useful on very small or new

infestations and with consistent, repeated use.

Always

wear gloves and wash hands to avoid skin irritation from

any secretions exuded by the plant or physical injury

from spines or thorns.

Many invasive plants can cause

irritation or photosensitivity if in contact with skin or eyes.

It is also important to properly dispose of invasive plants

as flower heads, seeds, root fragments, and stolons may

retain the ability to reproduce. This is also a reason to

avoid composting invasive plants. Invasive plants should

be double bagged and brought to the landfill – check with

your local municipality for designated invasive plant disposal

areas. Never compost invasive plants. Many invasive plant

species that are hand pulled when the flower is in bloom will

use remaining energy reserves to set seed. Always bag and

landfill flowers of invasive plant species even when there is

no indication of seed set at the time of pulling.

Hand-pulling can be effective for control of annuals,

biennials, simple perennials.

MOWING

Timely, regular mowing can be effective in reducing seed

formation if done regularly and with correct timing. Mowing

should be done frequently and multiple times a season,

ensuring it is done in the budding before flowering stage,

as mowing past this stage may lead to seed spread (see

hand pulling section above). It is also critical that all mowing

equipment is thoroughly cleaned before being transported to

avoid spreading the infestation.

Mowing may be effective for control of annuals, biennials,

and perennials if carried out as described above, particularly

when completed at the appropriate plant growth stage and

when combined with other control strategies. An integrated

approach is particularly important for creeping perennials, as

mowing alone may lead to increased root growth and spread

of creeping perennial infestations.

CULTIVATION

Cultivation is the practice of disturbing the soil to control an

infestation of weeds by destroying the roots. This control

method is mainly used in agriculture, and more effective

if repeated multiple times over a season or at least once

a year for several years. This method requires accurate

timing, because if it is timed improperly (e.g., when weeds

are going to seed), it can effectively spread the infestation.

This method is also not effective on invasive plant species

that reproduce vegetatively via root fragments, as

cultivation can multiply pieces and spread them further.

Cultivation can be effective on infestations with shallow

and non-reproductive root systems, and to inhibit seed

production and growth prior to planting a crop. Always

ensure equipment is cleaned thoroughly of soil, plant and

root fragments to avoid spreading the infestation to other

locations.

Cultivation can be effective for control of annuals and

biennials in field crops prior to seed-set. Cultivation may

lead to the increased spread of an infestation if dealing with

species that reproduce by root, stem or leaf fragments.

Cultivation should only be used in certain areas, such as

crop fields. Cultivation may increase the risk of soil erosion

by wind and water and should always be used with caution.

HERBICIDE

Herbicide can be an effective method of invasive plant

control with proper use and timing (for example, during

early active growth), especially when used in conjunction

with other control methods. Different herbicides affect the

plant’s system in different ways depending on how they

are applied and taken up by the plant. Herbicides also have

varying degrees of mobility in soil, residual effects (how

long they provide control for/remain in the environment),

and efficacy on certain plants. The effectiveness of

herbicide control is affected by application rate, mode of

action of the herbicide (how it enters the plant tissues),

and timing of treatment. Many herbicides cannot be used

near an open waterbody and may require Alberta-specific

applicator certification and permits. Approvals are required

for herbicide use within 30 metres of a waterbody.

Always

check product labels to ensure the herbicide is registered

for use on the target plant in Canada by the Pest

Management Regulatory Agency. Always read and follow

label directions for optimal effectiveness and safe use.

Consult your local professional (Agricultural Fieldman or

Certified Pesticide Dispenser) for more information.

Herbicides can be effective for control of annuals, biennials,

and perennials when applied according to the label

directions, particularly when applied at the appropriate

plant growth stage and when combined with other control

strategies.

It’s important to note that there are exceptions to every

rule. If you are interested in learning more about controlling

invasive plant species, please reach out to your municipal

Agricultural Fieldman, Weed Inspector in your town or city,

or contact the Alberta Invasive Species Council.

FIELD SCABIOUS

Species Prevalence

Some invasive species are already present and widespread

in Alberta (e.g., Canada thistle, ox-eye daisy, common tansy,

etc.), while others have been reported in only a few locations

or are not known to be present in Alberta. To provide a general

idea of the spatial extent of invasive plant species in Alberta,

each has been assigned into one of the following prevalence

categories. Note that invasive species distributions will change

over time and these categories were assigned to the best of

our knowledge at the time of publishing (2026).

Not known to

be present

Regionally

common

Widespread

Super

Widespread

Isolated

HABITAT PREFERENCES

Some invasive species prefer specific habitat types and

are more likely to be found in certain habitats than others.

To provide a general idea of invasive species habitat

preferences, each species has been assigned one or more

habitat types that they are known to inhabit. Note these are

general associations and some species will be found outside

of the habitats indicated in the guide.

BLACK HENBANE

HABITAT ICON LEGENDS:

Disturbed areas

Includes roadsides, gravel pits, industrial areas,

ditches, human or animal trails, waste areas

Crop and pasture land

Includes cropland, farmland, pastures

Grassland

Includes grasslands, parks, natural areas, open

areas, rangeland

Forests

Includes forest open areas, forest edges,

understory, parks

Aquatic areas

Includes waterbodies, streams, rivers, ponds,

forest wet areas, open water, lakes, marshes,

sloughs, irrigation canals, marshes, riparian areas

Urban areas

Includes ornamental beds, gardens, hedges,

ornamental water features

SCENTLESS CHAMOMILE

THE ALBERTA WEED CONTROL ACT &

REGULATION

Prohibited Noxious Weed

Means a plant designated in accordance with the

Weed

Control Regulation

as a Prohibited Noxious weed and

refers to the entire plant, including the plant’s seeds. This

weed designation can be seen as regulatory support for an

“Early Detection, Rapid Response” stage of invasive plant

management. Plants in this category are either not currently

found in Alberta or are found in few locations such that

eradication could be possible. Additionally, municipalities

have the authority to elevate a species to Prohibited

Noxious status within their jurisdiction through local bylaws.

Under the

Weed Control Act

a landowner has a

responsibility to

destroy a prohibited noxious weed

Noxious Weed

Means a plant designated in accordance with the

Weed

Control Regulation

as a Noxious Weed and refers to

the entire plant including the plant’s seeds. This weed

designation can be seen as regulatory support for a

“containment” stage of invasive plant management.

Plants listed in this category are considered too widely

distributed to eradicate. Additionally, municipalities have the

authority to elevate a species to Noxious status within their

jurisdiction through local bylaws.

Under the

Weed Control Act

a landowner has a

responsibility to

control a noxious weed

Weed Inspectors

Weed inspectors are appointed across Alberta, at provincial

and municipal levels, as required by the

Weed Control

Act

. Inspectors may enter land or personal property to

make inquiries, take samples or enforce a weed notice for

the regulated species, as identified in the

Weed Control

Regulation

2026 WEED CONTROL REGULATION UPDATES

The

Weed Control Regulation

is periodically updated to

reflect current science, management realities, and emerging

risks. The 2026 update includes revisions to the regulated

species list based on formal risk assessments that consider

multiple factors, including invasiveness, pathways of spread,

available control tools, impacts to animal and human health,

and the feasibility of long-term management.

As part of this update, several species were added to the

regulated list, and some classifications were adjusted (e.g.,

from prohibited noxious to noxious) to better align with

their distribution and management potential. Two species,

creeping bellflower and perennial sowthistle, were removed

from the provincial list due to their widespread distribution

and the limited effectiveness of provincial regulation as a

management tool.

Deregulation does not indicate that a species is no longer

a concern. Many invasive plants remain harmful and should

continue to be managed, and municipalities retain the

authority to regulate species through local bylaws where

appropriate.

The

Weed Control Act

and

Weed Control Regulation

are

available online at the King’s Printer website.

Contacts

If you have questions or concerns regarding the Alberta

Weed Control Act

or for assistance with weed identification

contact:



Alberta Invasive Species Council

abinvasives.ca



Your local county or municipal Agricultural Fieldman or

Weed Inspector

www.aaaf.ab.ca



Aquatic Invasive Species 24/7 Hotline:

1-855-336-BOAT (2628)



Alberta Native Plant Council

www.anpc.ab.ca



Alberta Ag-Info Centre Phone:

310-FARM (3276)

NODDING THISTLE

Bighead Knapweed

109

Cicer Milkvetch

Common Mullein

128

Common Tansy

147

Black Henbane

101

Common Barberry

Common St John’s-Wort

143

Yellow Flowers

Absinthe Wormwood

QUICK ID GUIDE

Mouse-Ear Hawkweed

Meadow Hawkweed

Leafy Spurge

142

Dalmatian Toadax

156

Yellow Flowers

Dyer’s Woad

European Hawkweed

Pale Yellow Iris

107

Perennial Sow Thistle

141

QUICK ID GUIDE

Yellow Flowers

Queendevil Hawkweed

Spoed Hawkweed

Puncturevine

133

Russian Olive

137

Saltlover

139

Rush Skeletonweed

136

Tall Buercup

Sulphur Cinquefoil

QUICK ID GUIDE

Yellow Flowers

Whiplash Hawkweed

Tansy Ragwort

135

Tall Hawkweed

Yellow Nutsedge

129

Yellowdevil Hawkweed

100

Yellow Clematis

Yellow Starthistle

144

Wild Parsnip

161

QUICK ID GUIDE

Yellow Flowers

Yellow Toadax

157

QUICK ID GUIDE

White Flowers

Autumn Olive

African Rue

Cut-Leaf Teasel

149

Baby’s Breath

Diuse Knapweed

113

Canada Thistle

152

Field Bindweed

Broad-Leaved Pepper-Grass

130

QUICK ID GUIDE

White Flowers

Garlic Mustard

Giant Hogweed

105

Hoary Cress

103

Japanese Knotweed

123

Hybrid Knotweed

122

Giant Knotweed

120

Hoary Alyssum

102

Himalayan Knotweed

121

QUICK ID GUIDE

White Flowers

Jimsonweed

108

Ox-eye Daisy

Queen Anne’s Lace

134

Wild Caraway

160

Thesium

150

White Cockle

Scentless Chamomile

QUICK ID GUIDE

Red/Purple/Pink Flowers

Common Crupina

Canada Thistle

152

Brown Knapweed

111

Black Swallowwort

145

Common Teasel

149

Black Knapweed

110

Alkali Swainsonpea

Bull Thistle

151

QUICK ID GUIDE

Red/Purple/Pink Flowers

Creeping Bellower

Dame’s Rocket

Field Scabious

140

Flowering Rush

Hound’s Tongue

106

Himalayan Balsam

Hybrid Knapweed

114

Great Burdock

QUICK ID GUIDE

Marsh Thistle

153

Red/Purple/Pink Flowers

Lesser Burdock

Jimsonweed

108

Nodding Thistle

154

Purple Loosestrife

126

Plumeless Thistle

155

Meadow Knapweed

115

Pale/European Swallowwort

146

QUICK ID GUIDE

Russian Knapweed

116

Spoed Knapweed

117

Red Bartsia

Saltcedar

138

Red/Purple/Pink Flowers

Tamarisk

138

Tyrol Knapweed

119

Woolly Burdock

Squarrose Knapweed

118

QUICK ID GUIDE

Green Flowers

Common Buckthorn

Japanese Brome

Medusahead

127

Downy Brome

Eurasian Water Milfoil

Jointed Goatgrass

Invasive Phragmites

132

Kochia

125

QUICK ID GUIDE

Green Flowers

Persian Darnel

131

Palmer Amaranth

Ventenata

158

Tall Waterhemp

159

QUICK ID GUIDE

Blueweed

Chicory

Orange Hawkweed

Blue/Orange Flowers

QUICK ID GUIDE

Burdocks

Great Burdock

Up to 3m tall, stems are thick and solid, grooved, sparsely hairy, very

large leaves, ruffled edges, taproot. Clusters of purple-pink flowers

on long stalks, hooked bracts below the flower. Outer floral bracts

spread outwards at maturity.

Lesser Burdock

Leaves large, heart shaped at base, woolly underside, reduced in size

upwards, alternately arranged on the stem. Up to 3m tall, stems are

thick and hollow, branched, reddish tinge, may be grooved or angular,

large and fleshy taproot. Clusters of purple-pink flowers on very short

stalks, hooked bracts below the flower. Floral bracts are slightly woolly.

Woolly Burdock

Large leaves, reduced in size upwards, heart shaped, woolly underneath,

alternately arranged on the stem. Up to 3m tall, stems are thick and

hairy. Clusters of purple-pink flowers, hooked bracts below the flower.

Floral bracts have dense, cobweb-like wool Taproot.

QUICK ID GUIDE

Hawkweeds

About Invasive Hawkweeds in Alberta

Hawkweeds in Alberta fall into two groups:

Pilosella

(invasive) and

Hieracium

(both native and invasive). In the

field, invasive

Pilosella

species can be identified by the type

and density of hairs on leaves and stems, one of the most

reliable visual features.

Pilosella

species typically form basal

rosettes and have few, if any, well-developed stem leaves,

in contrast to

Hieracium

species, which usually have well-

developed leaves along the stem.

Pilosella

species are listed as noxious, while invasive

Hieracium

species are prohibited noxious under Alberta’s

Weed Control Regulation

. Alberta also has three native

hawkweeds: white, woolly, and narrow-leaved hawkweed,

all in the

Hieracium

genus as well.

Hawkweed Tip:

Hieracium

→ many well-developed stem leaves - no invasive

species confirmed to be established

Pilosella

→ few or no stem leaves (often just 2–3 near the

base), several species regionally common

If you’re unsure about identification, contact the Alberta

Invasive Species Council for support.

QUEENDEVIL HAWKWEED

QUICK ID GUIDE

Meadow Hawkweed

Leaves are covered in long white hairs.

Difficult to differentiate

from orange hawkweed prior to flowering. Stems have long white

and long black hairs.

Yellow, dandelion-like flower

heads arranged in

compact, flat clusters. Stolons may be present.

Orange Hawkweed

Leaves are covered in long white hairs.

Difficult to differentiate

from meadow hawkweed prior to flowering. Stems have long white

and long black hairs.

Orange, dandelion-like flower heads

arranged

in compact, round-topped clusters. Stolons usually present.

Hawkweeds

Yellowdevil Hawkweed

Leaves have short white hairs and star-shaped hairs creating a

rough feel to the leaves

. Stems have black hairs and small star-

shaped hairs. Stolons usually not present.

100

QUICK ID GUIDE

Hawkweeds

Tall Hawkweed

Leaves are almost entirely hairless except for long white hairs on

underside of leaf along midvein

. Leaf margins may exhibit sparse

long white hairs. Sparse simple hairs on the stem. Stem has a waxy

feel. Stolons usually not present.

Queendevil Hawkweed

Basal leaves are long and narrow to oval or egg-shaped, with mostly

smooth edges (sometimes very finely toothed), and usually narrow

gradually where they attach to the stem. Upper surfaces are smooth

and hairless, while

lower surfaces have variable amounts of star-

shaped hairs

and longer simple hairs mostly concentrated along the

mid-vein. Similar to Tall hawkweed but with

stolons

Mouse-Ear Hawkweed

Solitary flower heads

with red stripes on underside of petals. Short

leaves, long hairs on top of leaf and mat of hairs below. Stolons

usually present.

QUICK ID GUIDE

Hawkweeds

Other Invasive Hawkweeds:

Common Hawkweed

Hieracium lachenalii

European Hawkweed

Hieracium sabaudum

Kingdevil Hawkweed

Pilosella floribunda

Polar Hawkweed

Hieracium atratum

Smooth Hawkweed

Hieracium laevigatum

Spotted Hawkweed

Hieracium maculatum

Wall Hawkweed

Hieracium murorum

Whiplash Hawkweed

Pilosella flagellaris

QUICK ID GUIDE

Knapweeds

Black Knapweed

Leaf edges are slightly toothed

or smooth, lance shaped, bracts

are black or dark brown in the

center with long black fringes,

hairy stems.

Brown Knapweed

Prefers cool, moist habitats.

Hairy, leaves are shallowly lobed,

not highly divided, bracts are

overlapping, brown and irregularly

torn looking.

110

Russian Knapweed

Bracts are green, rounded and

have papery edges. Young leaves

are hairy, upper leaves are narrow

with smooth margins, lobed

towards the base of the plant.

Rhizomatous.

116

Hybrid Knapweed

May have features of both Spotted

Knapweed and Diffuse Knapweed.

114

Meadow Knapweed

May have features of both Black

Knapweed and Brown Knapweed.

115

111

Diuse Knapweed

Flowers mostly white, sometimes

pink, plant is stiff and prickly,

leaves highly divided, and grey-

green bracts cream to brown,

comb -like with sharp ridged

spines.

113

QUICK ID GUIDE

Knapweeds

Spoed Knapweed

Bracts have dark spot on the tip

and short fringed edges. Lower

leaves deeply lobed, stem leaves

finely divided, highly branched.

Squarrose Knapweed

Flowers smaller than other

knapweeds, bracts have curved

spines, deeply divided leaves on

the lower portion of the plant,

spine-like leaves on the top. Spiny.

117

Tyrol Knapweed

Bracts are dark brown-black,

tipped with a dark fringe of

toothcomb like wiry lobes in 6-8

pairs. Large lance shaped broad

leaves.

119

118

Bighead Knapweed

One large yellow flower head per

branch tip. Bracts are fringed and

thin with papery edges.

109

QUICK ID GUIDE

Thistles

Marsh Thistle

Purple bracts spineless, long sticky hairs on stem and leaves,

unbranched stem.

153

Canada Thistle

Prickly stems/leaves, bracts have weak spines, stem branched,

flowers less than 2.5cm.

152

Bull Thistle

Spine-tipped, narrow bracts, droplet-shaped flower head, branched

stem, hairy leaves.

151

QUICK ID GUIDE

Thistles

Nodding Thistle

Large nodding flower head, dark green leaf with white midrib, spiny,

fine woolly hairstip, long hairs above and below leaf, stolons present.

154

Plumeless Thistle

Smaller flower than nodding thistle, tall, branched, spiny, leaves

winged or stalkless.

155

QUICK ID GUIDE

PLANT DIAGRAMS

INVASIVE PLANTS

PETAL

LEAF

OPPOSITE

ALTERNATE

WHORLED

LEAF

BRACT

FLOWER DIAGRAM

LEAF ARRANGEMENT

SEPAL

AWN

GLUME

BLADE

LIGULE

GRASS DIAGRAM

SPIKE

NODE

SPIKELET

SHEATH

AURICLE

Absinthe Wormwood

(Artemisia absinthium)

Native to Europe and Asia, absinthe wormwood (absinthe,

madderwort) is a perennial in the Asteraceae (Sunflower)

family.

Identication

Yellow,

nodding, button-like flowers

with few to no petals

arranged in loosely branched clusters on short stalks; bracts

are oval, gray-green with silky hairs. Leaves are pinnate, deeply

lobed; strong odour similar to sage. Stems are up to 60 cm

tall, may be multiple stems per plant, sometimes woody near

the base.

Leaves and stems are pale gray-green from dense

cover of fine hairs

Habitat

Prefers dry to moist areas, loamy,

gravel, clay or disturbed soils in full

sun, but can tolerate some shade.

Control

Reproduces by seed. Hand-pulling, repeated

cultivation or herbicide.

Similar Species

Non-native:

African rue

(Peganum harmala)

Native:

Non-shrub, pinnate-leaved, native sage/wormwood

species (

Artemisia

spp.). Absinthe wormwood is often taller

with egg-shaped pinnate leaves.

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

African Rue

(Peganum harmala)

Native to the desert areas of northern Africa and southern

Asia, African rue is a bushy perennial in the Nitrariaceae

(Nitre-bush) family. All parts of the plant are poisonous to

humans and livestock.

Identication

White or

yellowish-white

flowers with 5 petals, found at the

tip of stalks. Numerous stems, plants may grow 25-60 cm tall.

Leaves are finely divided

into many thin, thread-like segments,

alternate, bright green, and about 4–8 cm long. Seeds are

blackish-brown, triangular, about 2 mm, and the capsules are 3

chambered. Roots are deep and widely spreading.

Habitat

Inhabits arid and semi-arid environments,

both hot and cold, and tolerates hard,

sandy, and highly saline soils.

Control

Reproduces by seed and creeping roots. Aggressive,

repeated hand-pulling small infestations may be effective.

Mowing and burning are ineffective.

Similar Species

Non-native:

Absinthe wormwood (

Artemisia absinthium

)

Native:

None

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Alkali Swainsonpea

(Sphaerophysa salsula)

Native to Asia, alkali swainsonpea is a long-lived perennial

from the Fabaceae (Pea) family.

Identication

Flowers are initially colored red to pinky-brown, drying to

violet or purplish. Leaves are compound with 11–21 small oval

leaflets covered in fine white hairs along the edges. Stems

are upright to slightly spreading, branching, and typically

growing 30–60 cm tall, rarely up to 130 cm. Branches have

ridges along their length and may have few to many flat

hairs. Mature plants may look herb-like or shrubby. Extensive,

creeping roots capable of sprouting new plants.

Habitat

Prefers well-drained soils

and can tolerate alkaline

conditions.

Control

Reproduces by seed and creeping roots. Chemical control

options are limited, mowing may prevent seed production.

Similar Species

Non-native:

Alfalfa (

Medicago sativa

), sweetclovers

(

Melilotus

spp.)

Native:

Milk vetches (

Astragalus

ssp.), locoweeds

(

Oxytropis

spp.)

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Amaranth, Palmer

(Amaranthus palmeri)

Native to northwestern Mexico and the southwestern United

States, Palmer amaranth is an annual broadleaf species in the

Amaranth (Pigweed) family, Palmer amaranth is now recognized as

one of the most economically damaging herbicide-resistant weeds

in agriculture.

Identication

Leaves are rounded in young plants and become

oval to diamond-

shaped with pointed tips

as they mature, sometimes ending in a

tiny spine. The

leaf stalk is longer than the leaf blade

Flowers are

very small and form long, dense spikes

at the tips of stems. Plants

are male or female; male spikes feel softer than the female’s.

Habitat

Grows in many soil types and moisture conditions.

It can grow in full sun to dense shade, but shaded

plants may not produce seeds until they receive

more direct light.

Control

Reproduces by seed. Hand-pulling female plants may reduce seed

production, herbicide or mechanical control may be effective.

Known herbicide resistance.

Similar Species

Non-native:

Redroot pigweed (

Amaranthus retroflexus

), green

pigweed (

Amaranthus powellii

) and tall waterhemp (

Amaranthus

tuberculatus

) have leaf stalks shorter than their leaf blades.

Native:

None.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Autumn Olive

(Elaeagnus umbellata)

Native to Asia, autumn olive (Japanese silverberry) is a

perennial shrub in the Elaeagnaceae (Oleaster) family.

Identication

Flowers are white to light yellow and tube or bell-shaped

with 4 sepals. Leaves alternately arranged on stem,

silver-green colour, simple, wavy leaf edges, scales on the

underside, thorns can grow to 2.5 cm long. Multiple stems,

up to 6 m tall. Root woody and nitrogen-fixing. Fruit is small,

fleshy, red, egg-shaped with scales; up to 200,000 seeds

per year.

Habitat

Tolerant of a wide range of habitats.

Control

Reproduces by seed, root-crown sprouting and suckering.

Hand-pull seedlings.

Similar Species

Non-native:

Russian olive

(Elaeagnus angustifolia)

Native:

Thorny buffaloberry

(Shepherdia argentea)

wolf willow (silverberry)

(Elaeagnus commutata)

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Baby’s Breath, Common

(Gypsophila paniculata)

Native to Europe, common baby’s breath (maiden’s-breath) is

a perennial in the Caryophyllaceae (Carnation) family. Buyer

beware, this plant remains a common ornamental species in

floral displays.

Identication

Numerous small white flowers with 5 petals, star-shaped,

sweet scent. Leaves are opposite, narrow and 3-10 cm long,

prominent midvein; mainly on upper parts of stems. Stems

are bluish-green, up to 1 m tall with numerous branches; may

tumble at maturity. Large woody root up to 4 m deep. Up to

14,000 seeds per plant.

Habitat

Prefers dry, coarse to

sandy soils in full sun.

Control

Reproduces by seed. Hand-pulling, cultivation or herbicide.

Similar Species

Non-native:

Perennial pepper-weed

(Lepidium latifolium)

annual baby’s breath

(Gypsophila elegans)

, pink baby’s

breath

(G. scorzonerifolia)

Native:

Native pepper-grass

(Lepidium

spp.

)

often smaller

and have flowers with 4 petals

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Balsam, Himalayan

(Impatiens glandulifera)

Native to India, Himalayan balsam (policeman’s helmet, touch-

me-not) is an annual in the Balsaminaceae (Impatiens) family.

Identication

Irregular, pea-like, pink-purple-white flowers have 5 petals.

Leaves are simple, oblong, large with serrated edges;

oppositely arranged on the stem in whorls of 3. Red to purple

tinged stems are large, hollow, 4-sided (square), and grow

up to 120 cm. Shallow and fibrous roots. Seed pods explode

when ripe, shooting water-buoyant seeds up to 10 m away;

up to 4,000 seeds.

Habitat

Thrives in nutrient rich soils. Tolerant of partial shade, but is

frost and drought intolerant.

Regionally

common

Control

Reproduces by seed. Hand-pulling.

Similar Species

Non-native:

None

Native:

Purple monkeyflower

(Mimulus lewisii)

, Western

touch-me-not

(Impatiens noli-tangere)

, which has orange

flowers

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Barberry, Common

(Berberis vulgaris)

Native to Europe and Asia, common barberry is a deciduous

shrub in the Berberidaceae (Barberry) family. It is an alternate

host for stem rust fungus which affects wheat crops.

Identication

Yellow flowers occur in a hanging cluster, 10-20 stalked

flowers. Leaves alternately arranged in clusters, spines may

occur at leaf base, leaf margins with finely toothed edges,

dull green colour, 2-5 cm long. Stems woody, 1-3 m tall,

yellow-grey colour with

sharp spines

that occur in groups of

1-3. Creeping, woody root. Fruits are clusters of red berries;

individual berries are 1 cm long with 1-3 black seeds per berry.

Habitat

Tolerant of a wide range of conditions.

Control

Reproduces by seed, creeping roots and root fragments.

Hand-pull and herbicide.

Similar Species

Non-native:

Japanese barberry

(Berberis thunbergii)

Native:

None

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Bartsia, Red

(Odontites vulgaris)

Native to Europe, red bartsia is an annual in the

Orobanchaceae (Broomrape) family. It is unpalatable to

livestock, and may be parasitic to other plant species.

Identication

Reddish-purple snapdragon-like, tube-shaped flower with

fused sepals. Leaves are narrow, hairy with a toothed edge

and oppositely arranged. Stem is erect, branching, 15-30 cm

tall, and hairy. Taproot. Up to 1,400 seeds per plant.

Habitat

Thrives in a variety of soil types.

Not known to

be present

Control

Reproduces by seed. Hand-pulling or cultivation before

seed set.

Similar Species

None – unique in appearance

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Bellower, Creeping

(Campanula rapunculoides)

Native to Europe, creeping bellflower (creeping campanula)

is a creeping perennial in the Campanulaceae (Bellflower)

family.

Identication

Purple-blue, bell-shaped flowers are nodding with 5 fused

petals. Leaves are alternately arranged, heart-shaped, coarsely

toothed with pointed tip; lower leaves with longer leaf stalk,

upper leaves little to no leaf stalk. Stems unbranched, hairy,

grow up to 100 cm tall. Thick creeping roots. Up to 15,000

seeds per plant.

Habitat

Prefers light sandy to medium

loamy, well-drained soils that are

pH neutral. It is a common lawn

weed and is difficult to eradicate.

Control

Reproduces by seed and creeping roots. Hand-pulling,

digging, and smothering with tarps or cardboard.

Similar Species

Non-native:

Globe bellflower

(Campanula glomerata)

Native:

Native harebells (

Campanula rotundifolia

) which are

usually much shorter with smaller flowers and no creeping

roots

Widespread

WEED CONTROL ACT DESIGNATION:

UNREGULATED

Bindweed, Field

(Convolvulus arvensis)

Native to Africa, Asia and Europe, field bindweed (devil’s

vine, wild morning glory) is a perennial in the Convolvulaceae

(Morning Glory) family. It is mildly toxic to livestock.

Identication

White to pinkish flowers are 2.5 cm in diameter, funnel-

shaped with small bracts below the flowers; borne singly or

in pairs. Leaves are alternate, arrowhead-shaped with few

hairs or hairless. Stems up to 3 m long, trailing or climbing,

often with a slight twist and numerous shoots. Deep taproot

with extensive creeping roots. Up to 500 seeds per plant.

Habitat

Tolerates a wide range of conditions

but is shade intolerant.

Control

Reproduces by seed and creeping roots.

Hand-pull or herbicides before seed set.

Similar Species

Non-native:

Wild buckwheat

(Fallopia convolvulus)

distinguished by a dry sheath around each stem node

Native:

Hedge bindweed

(Calystegia sepium)

distinguished

by ‘larger flowers’

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Blueweed

(Echium vulgare)

Native to Europe, blueweed (viper’s bugloss) is a biennial in

the Boraginaceae (Borage) family.

Identication

Numerous blue, purple or pink funnel-shaped

flowers 1-2 cm long with 5 fused petals and short flower

stems alternately arranged on stalks; 4 stamens protrude

from flower centre. Basal rosette produced in first stage

of growth, flowering stem in second. Leaves covered with

stiff glandular hairs and dark flecks on the undersides. Basal

leaves are narrow with leaf stalks; stem leaves alternate,

smaller and stalkless. Stems up to 30-90 cm tall and covered

in short, stiff glandular hairs; one to several stems per plant.

Deep, black taproot with fibrous lateral roots. Up to 2,800

seeds per plant.

Habitat

Prefers warm gravel or sand

banks. Requires well drained soils and

does not tolerate shade.

Control

Reproduces by seed. Hand-pulling entire plant or

removal of flowering stalk. Herbicide at the rosette stage.

Similar Species

Non-native:

Paterson’s curse

(Echium plantagineum)

differentiated by the number of stamens, which is 2 for

Paterson’s curse and 4 for blueweed.

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Brome, Downy

(Bromus tectorum)

Native to the Mediterranean, downy brome (cheatgrass,

downy chess) is a winter annual in the Poaceae (Grass)

family.

Identication

Flowering spike droops to one side,

reddish-purple at

maturity

, 7-20 cm long; awns are reddish, twisted, long

and covered with soft hairs. Leaf blades are long, 2-4 mm

wide and covered with soft hairs; ligule is 1-3 mm long and

toothed. Stems are covered in soft hairs and up to 5-60 cm

tall dependent on moisture availability. Fibrous roots up to

1.5 m deep. Up to 5,000 seeds per plant.

Habitat

Prefers cool, semi-arid environments

with coarse sandy or loamy soils on

sunny, south/west facing slopes.

Control

Reproduces by seed. Hand-pulling, early spring grazing or

herbicide.

Similar Species

Non-native:

Japanese brome

(Bromus japonicus)

, field

brome

(B. squarrosus)

Native:

May resemble native brome grasses before seed-

set, which are perennial rather than annual.

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Brome, Japanese

(Bromus japonicus)

Native to central Europe, Pakistan and eastern Japan,

Japanese brome (Japanese chess) is a winter annual in the

Poaceae (Grass) family.

Identication

Flowering spike droops to one side,

brown and twisted at

maturity

; awns are tan, long (shorter than downy brome).

Leaf blades are flat, 2-4 mm wide and covered with soft

white hairs; ligule is 1.5 mm long, hairy and toothed. Stems

are covered in soft hairs, up to 90 cm tall and bent at the

base with swollen nodes. Fibrous, shallow roots.

Flattened

seeds.

Habitat

Prefers semi-moist environments

with sandy or clay soils and good litter

cover; intolerant of alkaline soils.

Control

Reproduces by seed. Hand-pulling or herbicide.

Similar Species

Non-native:

Downy brome

(Bromus tectorum)

field brome

(B. squarrosus)

Native:

May resemble native brome grasses before seed-

set, which are perennial rather than annual

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Buckthorn, Common

(Rhamnus cathartica)

Native to Eurasia, common buckthorn is a deciduous shrub in

the Rhamnaceae (Buckthorn) family.

Identication

Yellow to yellow-green flowers are small, inconspicuous with

4 petals. Male and female flowers on separate plants; male

flowers are clustered in leaf axils and female flowers in clusters

of 2-15. Leaves dull-to-dark green, glossy, oval-shaped with

pointed tip, 3-4 deeply veined, mostly opposite, sometimes

alternate near branch tips;

leaves remain green into late fall

and winter

. Branches opposite or alternate and often

end in

thorns

. Woody trunk up to 25 cm in diameter and up to

7 m tall, grey-brown bark, yellow beneath bark, rough texture.

Woody root. Fruits round and black with 3-4 seeds.

Habitat

Tolerant of a wide

range of conditions.

Control

Reproduces by seed, roots and cut stems will re-sprout.

Repeated hand-pulling, prescribed burns or herbicide.

Similar Species

Non-native:

None

Native:

Chokecherry

(Prunus virginiana)

, alder species

(Alnus

spp.

)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Burdock, Great

(Arctium lappa)

Native to temperate areas of Eurasia, great burdock is a

biennial in the Asteraceae (Sunflower) family.

Identication

Purple-pink, rarely white, flower head surrounded by

burrs

that occur in branched clusters at stem ends;

flower heads

are more than 2.5 cm across

. Basal rosette produced in first

year, flowering stem in second. Large leaves measuring

25-80 cm are alternately arranged, heart-shaped, woolly

underneath;

lower leaf stalks are solid

. Stems are slightly

grooved, sparsely hairy and up to 3 m tall. Fleshy, deep

taproot.

Burr-like seed pods

; up to 16,000 seeds per plant.

Habitat

Prefers moist soil but grows in

fertile or clay soils in full sun.

Control

Reproduces by seed. Hand-pull, digging or

herbicide. Cut or dig mature plants before seed set.

Similar Species

Non-native:

Lesser burdock

(Arctium minus)

, wooly burdock

(A. tomentosum)

Native:

Arrow-leaved coltsfoot

(Petasites sagittatus)

small leaf stages

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Burdock, Lesser

(Arctium minus)

Native to Eurasia, lesser burdock (common burdock) is a

biennial in the Asteraceae (Sunflower) family. The prickly,

hooked bracts were the inspiration for the invention of Velcro.

Identication

Purple-pink flower head surrounded by

burrs

that occur in

branched clusters at stem ends; flower heads less than 2.5 cm

across. Basal rosette produced in first stage of growth,

flowering stem in second. Large leaves (but smaller than other

burdocks) are alternately arranged, heart-shaped, woolly

underneath;

lower leaf stalks are hollow

. Stems are hollow,

slightly grooved with reddish tinge and up to 3 m tall. Fleshy,

deep taproot.

Burr-like seed pods

; up to 16,000 per plant.

Habitat

Tolerates a range of soil

conditions but prefers full sun

to partial shade.

Control

Reproduces by seed. Hand-pulling, herbicide, digging or

cultivating prior to seed set.

Similar Species

Non-native:

Great burdock

(Arctium lappa)

and wooly

burdock

(A. tomentosum)

. Leaves and burrs of lesser burdock

are smaller than those of other invasive burdocks.

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Burdock, Woolly

(Arctium tomentosum)

Native to Eurasia, woolly burdock is a biennial in the

Asteraceae (Sunflower) family.

Identication

Purple-pink flower head surrounded by

burrs covered

in cob web-like hairs

occur in branched cluster at stem

ends; flower heads less than 2.5 cm across. Basal rosette

produced in first stage of growth, flowering stem in second.

Large leaves are alternately arranged, heart-shaped, woolly

underneath; lower leaf stalks are both hollow and solid.

Stems are hairy, slightly grooved with purplish tinge and up

to 3 m tall. Fleshy, deep taproot.

Burr-like seed pods

; up to

16,000 seeds per plant.

Habitat

Tolerates a range of soil

conditions but prefers moist,

loamy soils with good drainage in full sun.

Control

Reproduces by seed. Herbicide, hand-pull or dig rosettes.

Cut or dig mature plants before seed set.

Similar Species

Non-native:

Great burdock

(Arctium lappa)

and lesser

burdock

(A. minus)

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Buercup, Tall

(Ranunculus acris)

Native to Europe, tall buttercup (meadow buttercup) is

a perennial in the Ranunculaceae (Crowfoot) family. It

contains a bitter oil that is toxic to livestock.

Identication

Yellow flowers with 5 waxy,

almost lacquered

petals sit on long branched stalks, 5 small, green sepals;

flowers up to 3 cm. Lower leaves are jagged, long-

stalked, deeply divided into 3-5 main segments; upper

leaves are smaller, hairy, stalkless and divided into 3-4

narrow segments. Stems grow up to 1 m, smooth, hollow,

sometimes hairy, leafy at base and branched above. Fibrous

roots. Spherical, hooked seed pod cluster; up to 250 seeds

per plant.

Habitat

Prefers moist to well-drained

humus soils but tolerates gravelly,

coarse soils with sufficient moisture.

Control

Reproduces by seed (mainly) and

rhizomes. Cultivation and reseeding with an

annual crop, mowing or hand-pulling before seed set, as long

as it is timed properly to avoid spreading seed or herbicide.

Similar Species

Non-native:

Sulfur cinquefoil

(Potentilla recta)

Native:

Yellow avens

(Geum aleppicum)

, native buttercup

(

Ranunculus

spp.)

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Chamomile, Scentless

(Tripleurospermum

inodorum)

Native to Eurasia, scentless chamomile (mayweed, false

chamomile) is an annual, biennial or short-lived perennial in

the Asteraceae (Sunflower) family.

Identication

Solitary daisy-like flowers have white petals surrounding a

yellow centre at the branch ends. Basal rosette produced

in first stage of growth, flowering stem in second.

Leaves

alternate, very finely divided (carrot-like) and highly

branched.

Stems are highly branched, slightly reddish and

up to 1 m tall or as small as 5 cm. Fibrous roots.

Habitat

Adapted to heavy clay soils, but is

tolerant of a wide range of conditions,

including flooding and dry sites.

Control

Reproduces by seed. Hand-pulling or

herbicide, cultivation of rosettes, mowing

(may regrow from roots) or biocontrol agents

(a seed-head feeding weevil,

Omphalapion hookeri

, and a

gall midge,

Rhopalomyia tripleurospermi

Similar Species

Non-native:

Ox-eye daisy

(Leucanthemum vulgare)

leaves

differ

Native:

Aster (

Symphyotrichum

and

Eurybia

spp.)

Widespread

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Chicory

(Cichorium intybus)

Native to southern and central Europe, Africa, and parts of

western Asia, chicory is in the Asteraceae (Aster) family and is a

deep-tap rooted perennial that sometimes behaves as a biennial.

Identication

Bright blue (sometimes white), daisy-like flowers with squared,

toothed petal tips, typically found in small clusters along the upper

stems. Stems are upright, stiff, and branching. A low-growing

rosette of dandelion-like leaves forms early, with leaves that are

elongated, lobed, and slightly hairy; upper leaves are smaller, lack

stalks, and clasp the stem. Plants can reach up to 2 m in height.

Produces small, brown, ridged seeds contained in wedge-shaped

structures.

Habitat

Favours lime-rich soils, but tolerates a wide range

of conditions and is commonly found in disturbed

sites such as fields, roadsides, fence lines,

pastures, and neglected turf.

Control

Reproduces by seed. Herbicide, hand-pulling, removing as much

of the taproot as possible.

Similar Species

Non-native:

Prickly lettuce (

Lactuca serriola

), distinguished by

yellow flowers

Native:

Tall blue lettuce (

Lactuca biennis

), distinguished by

smaller to less showy flowers and a less rigid stem

Isolated -

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

Cicer Milkvetch

(Astragalus cicer)

Native to Europe, cicer milkvetch (chickpea milkvetch) is a

perennial in the Fabaceae (Pea) family.

Identication

Spike-like clusters of 15-60 yellow to white pea-shaped

flowers on a long smooth stalk; several dark green prongs

at the tip end protrude from the hairy flower base. Leaves

are pinnately compound with 10-13 pairs of oblong leaflets.

Stems are hollow, fairly weak and often sprawl, creating

dense tangled mats. Short, branched taproot.

Cluster of

egg-shaped fruits are hairy and turns stiff and black at

maturity.

Habitat

Prefers disturbed, partly-

shaded areas, moderately

coarse or moist soils. Tolerates a wide range

of moisture, soil types, pH and salt levels.

Control

Reproduces by seed and rhizomes. Repeated removal of top

growth over the growing season.

Similar Species

Non-native:

Crownvetch

(Securigera varia)

, tufted vetch

(Vicia cracca)

Native:

Wild licorice

(Glycyrrhiza lepidota),

native milkvetch species

(Astragalus

spp.

)

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

Cinquefoil, Sulphur

(Potentilla recta)

Native to eastern Europe and the Mediterranean, sulphur

cinquefoil is a long-lived perennial in the Rosaceae (Rose)

family. It is unpalatable to livestock.

Identication

Pale yellow flowers have 5 petals with deeply notched

tips around a yellow centre; 5 hairy sepals below. Leaves

palmately compound with 5-7 toothed leaflets;

leaf

underside is green

. Few basal leaves, most grow along

stem; leaf stalk length and size decrease toward the top of

the plant. One to several erect, branched stems, 30-60 cm

tall;

stems have hairs perpendicular to stem and leafstalks

Fibrous woody roots. Up to 1,400 seeds per season.

Habitat

Prefers semi-arid regions, but

can tolerate a wide range of soil

conditions and climates.

Control

Reproduces by seed. Hand-pulling, cultivation and herbicide.

Similar Species

Non-native:

Tall buttercup

(Ranunculus acris)

Native:

Resembles several native cinquefoil species,

particularly graceful cinquefoil (

Potentilla gracilis

), which has

darker yellow flowers and silvery-white leaf undersides.

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Clematis, Yellow

(Clematis tangutica)

Native to Asia, yellow clematis (golden clematis, golden

tiara, helios) is a perennial vine in the Ranunculaceae

(Buttercup) family. Buyer beware, this plant may be available

as an ornamental plant for purchase.

Identication

Lemon-yellow, nodding flowers

with 4 long petals are

bell-shaped; born either singly or in small groups of 2-3 on a

short stalk. Compound leaves with 5-7 lance-shaped leaflets,

5-6 cm long; edges coarsely toothed and tips pointed,

undersides slightly hairy. Several branching stems up to

3-4 m long; young stems are pliable, older stems become

woody. Long taproot. Seed heads or

‘puffballs’

are clusters

of oval seeds with long silky tails.

Habitat

Tolerant of cold, drought and nutrient

poor soil conditions but prefers full sun.

Control

Reproduces by seed and can regenerate from crown of the

rootstock. Repeated hand-pulling before seed set.

Similar Species

Non-native:

Clematis

(Clematis akebioides)

Native:

Purple clematis

(Clematis occidentalis)

, white

clematis

(C. ligusticifolia)

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Cockle, White

(Silene latifolia

subsp.

alba.)

Native to Europe, white cockle (white campion, evening cockle)

is a biennial or short-lived perennial in the Caryophyllaceae

(Pink) family. Plants are either male or female, so not every plant

produces seed.

Identication

White to pale pink flowers with 5 notched petals

arranged in numerous clusters; only open at night. Tubular,

bulbous, purple-green sepals surround flower base; male sepals

have 10 veins and female sepals have 20 veins, often redder,

inflating as it ripens. Basal rosette produced in first stage of

growth, flowering stem in second. Leaves opposite, hairy, oblong

or lance-shaped with pointed tips. Stems are hairy, erect or

laterally spreading, grow 120 cm tall and swell at the nodes.

part of the plant is sticky.

Deep taproot and lateral roots. Seed

pods are smooth, bulb-like and hairless, 10-15 mm long; up to

25,000 seeds per plant.

Habitat

Prefers full sun and rich, well-drained soils.

Regionally

common

Control

Reproduces by seed. Repeated mowing will reduce seed

production; do not cultivate. Herbicide can be effective.

Similar Species

Non-native:

Bladder campion

(Silene vulgaris)

not hairy or sticky,

night-flowering catchfly

(S. noctiflora)

hairy, upper stems sticky

Native:

Silene species (

Silene

spp.)

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Crupina, Common

(Crupina vulgaris)

Native to the Mediterranean, common crupina (bearded

creeper) is a winter annual in the Asteraceae (Sunflower)

family.

Identication

Pink to purple flowers with 1-7 scale-like bracts. Rosette and

stem leaves pinnately lobed, alternate with short stiff spines

and smaller toward top of the plant. Stem is rigid, covered

with short stiff spines and heavily branched in the upper

portion; grows to 1 m. Shallow taproot.

Habitat

Prefers well-drained soils, but tolerant of a wide range of soil

and climatic conditions.

Not known to

be present

Control

Reproduces by seed. Repeated hand-pulling or herbicide.

Similar Species

None - unique in appearance

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Daisy, Ox-eye

(Leucanthemum vulgare,

formerly

Chrysanthemum leucanthemum)

Native to Europe, ox-eye daisy is a perennial in the

Asteraceae (Sunflower) family. Buyer beware, this plant is

often a contaminant in wildflower seed mixes.

Identication

Solitary daisy-like flowers have 20-30 white petals slightly

notched at tips surrounding a yellow centre at the branch

ends.

Lower leaves are spoon-shaped with lobed or

toothed edges and long leaf stalks; upper leaves are

alternate, narrow and clasp the stem.

Stems are smooth,

often grooved, sometimes branch and up to 1 m. Creeping

roots. Up to 26,000 seeds per plant.

Habitat

Tolerates a variety of habitats including

those with poor soil conditions, but

prefers nutrient poor soils.

Control

Reproduces by seed and creeping roots.

Repeated mowing, hand-pulling, herbicide or

grazing may reduce seed production.

Similar Species

Non-native:

Scentless chamomile

(Tripleurospermum

inodorum)

leaf arrangement and shape differs, shasta daisy

(Leucanthemum x superbum)

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Dame’s Rocket

(Hesperis matronalis)

Native to Europe, dame’s rocket (dame’s violet) is a biennial

or short-lived perennial in the Brassicaceae (Mustard) family.

Buyer beware, this plant remains a common ornamental

species and is frequently found in “wildflower” seed mixes.

Identication

Pink-purple-white flowers with 4 petals borne in loose

clusters at tops of stems. Basal rosette produced in first

stage of growth, flowering stem in second. Leaves are lance-

shaped, alternate with small hairs on both sides and toothed

edges. Stems are often branched and up to 1 m tall. Shallow,

slender root. Thin, long seed pods are 5-10 cm and hold tiny

black seeds; up to 20,000 seeds per plant.

Habitat

Prefers moist habitats and rich,

humus soils. It is tolerant of

partial shade.

Control

Reproduces by seed. Repeated hand-pulling before seed set.

Similar Species

Non-native:

Garden phlox

(Phlox paniculata)

Native:

Common fireweed

(Epilobium angustifolium)

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Dyer’s Woad

(Isatis tinctoria)

Native to Russia, dyer’s woad (woad) is a winter annual,

biennial or short-lived perennial in the Brassicaceae

(Mustard) family.

Identication

Clusters of small, 4-petaled yellow flowers form a dense, flat-

topped flower head. Basal rosette produced in first stage of

growth, flowering stem in second. Leaves bluish-green with

white midrib and powdery white film on upper leaf surface

Rosette leaves with long slender stalks, wide near the tip,

covered with soft hairs; upper stem leaves alternate, lance-

shaped, clasping and hairless. Stem is erect, somewhat

woody and heavily branched in the upper portion; grows to

120 cm. Fleshy taproot with lateral roots. Hanging fruit pods

are purple-brown, tear drop shaped and hold 1-2 brown-

yellow, cylindrical seeds; up to 10,000 seeds per year.

Habitat

Prefers well drained soils. Unlike

other mustards it does not

require disturbance to become established.

Control

Reproduces by seed and roots. Hand-pulling before seed set.

Similar Species

Non-native:

None

Native:

Native mustards (

Draba

spp.)

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Eurasian Water Milfoil

(Myriophyllum spicatum)

Native to Eurasia and Africa, Eurasian water milfoil is an

aquatic perennial in the Haloragaceae (Water Milfoil) family.

Identication

Clusters of small, 4-petaled yellow flowers attach directly to

a pinkish flowering spikelet growing 5-20 cm above water

surface. Leaves rarely extend above water surface and are red

to green, occur in whorls of 3-4 around the stem with

than 12 pairs of fine, closely spaced leaflets

. Pink to reddish

stem is slender, branching, leafless towards the base; can

extend up to 10 m. Underground runners with roots found at

base and along stem; can re-root from stem fragments. Fruit

capsule is hard, floating, segmented and holds 4 seeds.

Habitat

Grows submersed in fresh, still or

flowing waters up to 10 m deep.

Tolerant of a variety of water conditions.

Control

Reproduces by seed and root or stem fragments. Hand-

pulling and herbicide.

Similar Species

Non-native:

Variable-leaf water milfoil

(Myriophyllum

heterophyllum)

Native:

Northern water milfoil

(Myriophyllum

sibiricum)

has less than 12 pairs of leaflets

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Flowering Rush

(Butomus umbellatus)

Native to Europe, Africa and Asia, flowering rush (grassy

rush, water gladiolus) is an aquatic perennial and the only

member of the Butomaceae family.

Identication

Umbrella-shaped clusters of pink to white flowers with 3

petals and 3 purple-brown bracts at the end of stems. Erect

or floating leaves are sword-shaped, triangular in cross-

section with twisted tips and originate from the base of the

plant; base is red-tinged. Stem is leafless with a round cross-

section. Creeping roots can form small bulb-like projections

that break-off and can start new infestations. Fruit is brown

to black, beaked and inflated; Canadian populations have not

been known to produce viable seeds.

Habitat

Can grow completely submerged in depths

of 3-6 m or partially submerged in freshwater.

Control

Reproduces by root fragments. Hand-pulling,

digging and herbicide.

Similar Species

Non-native:

None

Native:

Native: Cattails, rushes, sedges and bur-reeds

Regionally

common

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Garlic Mustard

(Alliaria petiolata)

Native to Europe and Asia, garlic mustard (poorman’s

mustard, garlicwort, hedge garlic) is a biennial in the

Brassicaceae (Mustard) family.

Identication

White 4-petaled flowers with yellow centres form clusters

at the end of stems. Basal rosette produced in first stage of

growth, flowering stem in second. Leaves alternate, heart-

to-spade-shaped with toothed edges, becoming smaller

upwards on the stem;

garlic odor when crushed

. Stems

usually with 1-2 branches per plant and grow up to 1.5 m,

upper stems have little to no branching.

White, slender

taproot with crook or s-bend just below ground level.

Long,

narrow fruit pods, up to 6 cm long; up to 850 seeds per plant.

Habitat

Prefers rich, moist, forest soils with dense shade but can

tolerate full sun.

Isolated

Control

Reproduces by seed. Hand-pulling and digging.

Similar Species

Non-native:

None

Native:

Canada violet

(Viola canadensis)

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Goatgrass, Jointed

(Aegilops cylindrica)

Native to Asia, jointed goatgrass (jointgrass) is a winter

annual in the Poaceae (Grass) family. Similarities to wheat

make it difficult to control in cereal crops.

Identication

Spike is cylindrical with jointed seed heads (spikes) clustered

in narrow spikelets; each spikelet contains up to 5 flowers

and is 1 cm long. Lower spikelets lack an awn at the tip and

upper spikelets have long, narrow awns. Leaf blades narrow,

2-5 mm wide and covered with evenly spaced hairs at a

90° angle on the leaf edge; sheath open, with hairy auricles.

Stem is branched up to 80 cm tall. Fibrous root system.

Seeds are red to brown, grooved and up to 9 mm long.

Habitat

Prefers sites that are dry and open.

Not known to

be present

Control

Reproduces by seed. Mechanical removal before flowering.

Similar Species

Non-native:

Other invasive grasses, wheat (introduced

agronomic)

Native:

Native wheatgrasses

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, Common

(Hieracium lachenalii)

Native to Europe, common hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are

difficult to tell apart.

Identication

Yellow, dandelion-like flowers in small clusters

4–12 per plant with star-shaped and gland-tipped hairs.

Leaves are grey-green with noticeable teeth

, with several

along the stem becoming smaller upward. Stems are erect

and often solitary, with glandular and a few star-shaped

hairs, growing 20–80 cm tall and

lacking stolons

Habitat

Prefers dry to moderately

moist places such as roadsides,

gravel riverbeds, forest openings

and other disturbed areas in lowland and

mountainous regions.

Control

Reproduces by seed and creeping

roots. Hand-pull or herbicide prior to flowering. Applying

treatment to plants while they are flowering can promote

seed production.

Similar Species

Non-native:

Other invasive hawkweeds

(

Pilosella

spp.) can be distinguished based on characteristics of

stem and leaf hairs.

Native and invasive:

Hieracium

species,

distinguished by leafy stems with well-developed stem leaves,

unlike the mostly basal leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, European

(Hieracium sabaudum)

Native to Europe, European hawkweed is a perennial in

the Asteraceae (Sunflower) family. It is part of a group of

closely related yellow-flowered hawkweed species, which

are difficult to tell apart.

Identication

Yellow, dandelion-like flower heads in small

clusters of 3–12 per plant with bracts covered in dark, long

hairs. Leaves are long and narrow with smooth edges, many

found along the stem and crowded near the base, becoming

smaller upward, with coarse hairs underneath. Stems are

thick and upright, 40–130 cm tall, with many long, firm hairs,

especially on the lower stem.

Habitat

Prefers high-elevation areas

such as mountain grasslands, rocky

slopes, and other open, exposed sites

with little to no canopy cover.

Control

Reproduces by seed and creeping

roots. Hand-pull or herbicide prior to flowering. Applying

treatment to plants while they are flowering can promote

seed production.

Similar Species

Non-native:

Other invasive hawkweeds

(

Pilosella

spp.) can be distinguished based on characteristics

of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy stems with well-developed

stem leaves, unlike the mostly basal leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, Kingdevil

(Pilosella floribunda)

Native to Europe, kingdevil hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are difficult to

tell apart.

Identication

15–25 yellow flower heads in a loose cluster with the outer bracts

hairy,

may have red stripes underneath

. Basal leaves are long and

narrow to oval or egg-shaped. Upper leaf surface mostly hairless or

with a few long simple hairs;

lower surface and midrib have dense

short, simple hairs. Lower stem with dense simple hairs; stolons

leafy and typically present

. Grow to 15-50 cm tall.

Habitat

Prefers high-elevation areas such as

mountain grasslands, rocky slopes,

and other open, exposed sites with little

to no canopy cover.

Control

Reproduces by seed and creeping roots. Hand-pull or herbicide

prior to flowering. Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.) can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Meadow

(Pilosella caespitosa,

formerly

Hieracium caespitosum)

Native to Europe, meadow hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are difficult to

tell apart.

Identication

Yellow, dandelion-like flowers in loose clusters

20-50 per plant

. Leaves are hairy, narrow, lance-shaped, dark

green upper, light green underside; leaf edges entire or minutely

toothed.

Basal leaves covered in long, white hairs; shorter star-

shaped hairs on underside only

. Stems erect, solitary with simple,

glandular and star-shaped hairs and grow 20-70 cm tall. Rhizomes

have fibrous roots, short stolons. Seeds are dandelion-like and

readily wind-dispersed.

Habitat

Prefers moist, well-drained soils,

low in organic matter.

Control

Reproduces by seed and

creeping roots. Handpull or herbicide prior to

flowering. Applying treatment to plants while they

are flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.), many of which also have yellow flowers and orange

hawkweed prior to flowering.

Native and invasive:

Hieracium

species, which include both native

and invasive hawkweeds, are distinguished by their leafy stems

with well-developed stem leaves, compared to the mainly basal

leaves of invasive

Pilosella

species.

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Mouse-Ear

(Pilosella officinarum,

formerly

Hieracium pilosella)

Native to Europe, mouse-ear hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely related

yellow-flowered hawkweed species, which are difficult to tell apart.

Identication

Yellow, dandelion-like flowers are

solitary on the end

of each stem

(unlike meadow hawkweed); flowers will sometimes

have red stripes underneath, bracts covered in star-shaped hairs. Basal

rosette leaves are hairy, narrow, lance-shaped,

dark green above, light

green below

. Leaf underside appears white due to dense hairs. Stems

erect, leafless and covered with bristly hairs; up to 30 cm tall (shorter

than other hawkweeds). Rhizomes have fibrous roots, mat-forming

stolons. Seeds are dandelion-like and readily wind-dispersed.

Habitat

Prefers well-drained, coarse

textured soils.

Control

Reproduces by seed and creeping

roots. Handpull or herbicide prior to flowering.

Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.), many of which also have yellow flowers. Mouse-ear

hawkweed can be distinguished by having a single flower (or

occasionally two) at the end of the stem.

Native and invasive:

Hieracium

species (both native and invasive),

which are distinguished by their leafy stems with well-developed

stem leaves, unlike the mostly basal leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Orange

(Pilosella aurantiaca,

formerly

Hieracium aurantiacum)

Native to Europe, orange hawkweed (devil’s paintbrush) is a

perennial in the Asteraceae (Sunflower).

Identication

Compact, umbrella-like clusters of r

ed-orange dandelion-like

flowers on the end of each stem

; bracts covered in coarse black

hairs. Basal rosettes have hairy, narrow, club-shaped leaves with

numerous hairs on upper and lower leaf. Leaf edges may be entire

or slightly toothed. Stems are erect and solitary with bristly hairs

and few to no leaves; up to 60 cm tall. Rhizomes have fibrous

roots, mat-forming stolons. Seeds are dandelion-like; up to 1,500

seeds per plant.

Habitat

Prefers well-drained, coarse

textured soils.

Control

Reproduces by seed and creeping roots. Handpull or herbicide

prior to flowering. Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds,

Pilosella

spp. (all have

yellow flowers), especially meadow hawkweed.

Native and

invasive:

Hieracium

species, which include both native and

invasive hawkweeds, are distinguished by their leafy stems

with well-developed stem leaves.

Native:

mountain dandelion

(

Agoseris aurantiaca

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Polar

(Hieracium atratum)

Native to Europe, polar hawkweed is a perennial in the Asteraceae

(Sunflower) family. It is part of a group of closely related yellow-

flowered hawkweed species, which are difficult to tell apart.

Identication

Yellow, dandelion-like flower heads in loose clusters of 2–10 per

plant, with

bracts covered in dark, often sticky hairs

with a few

star-shaped hairs. Leaves are narrow with a few coarse, outward-

pointing teeth, mostly at the base, with only 2–4 smaller leaves

along the stem, and

simple hairs on upper and finer on lower

surfaces

. Stems are upright, branching near the top, 20–40 cm

tall,

without stolons

Habitat

Prefers high-elevation areas such as

mountain grasslands, rocky slopes, and other

open, exposed sites with little to no canopy cover.

Control

Reproduces by seed and creeping roots. Hand-pull or herbicide

prior to flowering. Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.) can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, Queendevil

(Pilosella praealta)

Native to Europe, Queendevil hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are difficult to

tell apart.

Identication

15–30

yellow flower heads, bases of bracts typically

have grey, brown, or clear gland-tipped hairs. Basal leaves are long

and narrow to oval or egg-shaped, with mostly smooth edges.

Upper surfaces are smooth and hairless, while

lower surfaces have

variable amounts of star-shaped hairs

and longer simple hairs

mostly concentrated along the mid-vein. Stems are upright and

sometimes branch near the top with sparse simple hairs. Plants are

typically 25–80 cm tall. Has

leafy stolons

(runners).

Habitat

Prefers high-elevation areas

such as mountain grasslands, rocky

slopes, and other open, exposed sites

with little to no canopy cover.

Control

Reproduces by seed and creeping roots.

Hand-pull or herbicide prior to flowering. Applying

treatment to plants while they are flowering can promote seed

production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.) can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Isolated

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Smooth

(Hieracium laevigatum)

Native to Europe, smooth hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are

difficult to tell apart.

Identication

Yellow, dandelion-like flower heads in clusters of 10–25 per

plant, lacking hairs. Leaves are broad with coarse teeth, stem

leaves becoming smaller upward. Stems with many star-

shaped and dark hairs, are upright, 40–110 cm tall.

Habitat

Prefers high-elevation areas

such as mountain grasslands, rocky

slopes, and other open, exposed sites

with little to no canopy cover.

Control

Reproduces by seed and creeping

roots. Hand-pull or herbicide prior to flowering. Applying

treatment to plants while they are flowering can promote

seed production.

Similar Species

Non-native:

Other invasive hawkweeds,

Pilosella

spp. can

be distinguished based on characteristics of stem and leaf

hairs.

Native and invasive:

Hieracium

species, distinguished

by leafy stems with well-developed stem leaves, unlike the

mostly basal leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, Spoed

(Hieracium maculatum)

Native to Europe, spotted hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are difficult to

tell apart.

Identication

Yellow, dandelion-like flower heads in loose clusters of 2–10 per

plant, with bracts covered in dark and sometimes sticky hairs.

Leaves have coarse, sharp teeth and

often show purple spots on

the upper surface

. Stems are upright, 20–80 cm tall, and branch

near the top.

Habitat

Prefers high-elevation areas such as

mountain grasslands, rocky slopes, and

other open, exposed sites with little to no

canopy cover.

Control

Reproduces by seed and creeping roots. Hand-pull or herbicide

prior to flowering. Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds,

Pilosella

spp. can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, Tall

(Pilosella piloselloides,

formerly

Hieracium piloselloides)

Native to Europe, tall hawkweed is a perennial in the Asteraceae

(Sunflower) family. It is part of a group of closely related yellow-

flowered hawkweed species, which are difficult to tell apart.

Identication

Yellow ray flowers in open, round-topped clusters of 11-20 at the

top of the stem.

Leaves almost entirely hairless except for long,

white hairs on the underside of leaf midvein. Leaf edges may

have long, white hairs.

Few if any stem leaves.

Stem is waxy with

long white, and sparse black hairs.

Plants 40 – 90 cm tall. Fibrous

and creeping roots and

no stolons

. Seeds are dandelion-like and

are readily wind-dispersed.

Habitat

Prefers well drained, coarse

textured soils, moderately low in organic matter.

Control

Reproduces by seed and creeping roots. Handpull or herbicide

prior to flowering. Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.); tall

hawkweed is distinguished by characteristics of leaf hairs and

may be confused with queendevil hawkweed, which has stolons

(absent in tall hawkweed).

Native and invasive:

Hieracium

species, distinguished by leafy stems with well-developed stem

leaves, unlike the mostly basal leaves of

Pilosella

species.

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Wall

(Hieracium murorum)

Native to Europe, wall hawkweed is a perennial in the Asteraceae

(Sunflower) family. It is part of a group of closely related yellow-

flowered hawkweed species, which are difficult to tell apart.

Identication

Yellow, dandelion-like flower heads in clusters of 4–15 per plant,

densely covered in star-shaped and dark hairs. Leaves are mostly

smooth or slightly toothed, with broad, rounded to heart-shaped

basal leaves that do not narrow at the base. Leaves hairless or

sparsely hairy on top with a few star-shaped hairs underneath.

Stems are upright, 20–80 cm tall, usually leafless or with only 1–2

small leaves near the base.

Habitat

Prefers high-elevation areas such as

mountain grasslands, rocky slopes, and

other open, exposed sites with little to no

canopy cover.

Control

Reproduces by seed and creeping roots. Hand-pull or herbicide

prior to flowering. Applying treatment to plants while they are

flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.), can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

Hawkweed, Whiplash

(Pilosella flagellaris)

Native to Europe, Whiplash hawkweed is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are difficult to

tell apart.

Identication

Typically has 2–6 yellow flower heads, petals may

have red-orange stripes underneath, outer bracts covered in

star-shaped, dark gland-tipped, and long hairs. Basal leaves are

long and narrow to spoon shaped, rounded at the tip and narrow

at the base, typically with smooth edges. Upper surface with few

to many long, simple hairs; lower surface with dense star-shaped

and long, simple hairs. Stems may branch once or twice along their

length, 6–20 cm tall with leafy stolons.

Habitat

Prefers high-elevation areas

such as mountain grasslands, rocky

slopes, and other open, exposed sites

with little to no canopy cover.

Control

Reproduces by seed and creeping

roots. Handpull or herbicide prior to flowering. Applying treatment

to plants while they are flowering can promote seed production.

Similar Species

Non-native:

Other invasive hawkweeds,

Pilosella

spp. can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Not known to

be present

WEED CONTROL ACT DESIGNATION:

NOXIOUS

Hawkweed, Yellowdevil

(Pilosella glomerata,

formerly

Hieracium glomeratum)

Native to Europe, yellowdevil hawkweed is part of the ‘Meadow

Hawkweed Complex’ (Subgenus

Pilosella

). It is a perennial in the

Asteraceae (Sunflower) family. It is part of a group of closely

related yellow-flowered hawkweed species, which are difficult to

tell apart.

Identication

Yellow ray flowers in open, round-topped clusters

of 15-25 at the top of the stem.

Leaves appear hairless, but have

short, white and star shaped hairs creating a rough feel to the

leaves.

Basal leaves broadly lance-shaped, few if any stem leaves.

Stems,

25-90 cm tall,

have black hairs and small star-shaped

hairs.

Fibrous and creeping roots. Seeds are dandelion-like and are

readily wind-dispersed.

Habitat

Preference for well-drained soils,

low in organic matter, typically shade

intolerant.

Control

Reproduces by seed and creeping roots.

Handpull or herbicide prior to flowering. Applying

treatment to plants while they are flowering can promote seed

production.

Similar Species

Non-native:

Other invasive hawkweeds (

Pilosella

spp.), can be

distinguished based on characteristics of stem and leaf hairs.

Native and invasive:

Hieracium

species, distinguished by leafy

stems with well-developed stem leaves, unlike the mostly basal

leaves of

Pilosella

species.

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

100

Henbane, Black

(Hyoscyamus niger)

Native to the Mediterranean, black henbane (stinking

nightshade) is a biennial in the Solanaceae (Nightshade)

family. All parts of the plant are toxic to humans and wildlife.

Identication

Yellow to cream coloured flowers are bell-

shaped with 5 lobes, many purple veins, and a dark purple

centre

; multiple flowers per stem. Flowers and leaves have

a rotting garbage-like odour. Basal rosette produced in

first stage of growth, flowering stem in second. Leaves are

alternate, large, slightly sticky, up to 45cm long, stalkless with

variably lobed edges. Stems are branched or unbranched,

robust and up to 1 m tall. The entire plant is covered with

hairs. Thick, fleshy taproot.

Bell-shaped, yellow to cream

coloured papery seed capsules with triangular edges

usually aligned on one side of the stem

; up to half a million

seeds per season.

Habitat

Requires well drained soil

but tolerant to a wide range of soil

textures and pH. It does not tolerate shade.

Control

Reproduces by seed. Hand-pulling,

mowing, herbicide or cultivating rosettes or cut stem at the

base of the plant before seed set.

Similar Species

None – unique in appearance

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

101

Hoary Alyssum

(Berteroa incana)

Native to Europe, hoary alyssum (hoary false madwort) is an

annual, biennial or short-lived perennial in the Brassicaceae

(Mustard) family.

Identication

Clusters of small, white flowers with yellow

centre and 4 deep-notched petals (appear as 8 petals) along

stem axis. Basal rosette produced in first stage of growth,

flowering stem in second. Leaves alternate, greyish green

with

star-shaped hairs

. Rosette leaves long with slender

stalks; stem leaves face upward, pressed to the stem;

stalkless ascending. Purplish stems are erect, branched,

grow to 90 cm tall and covered with star-shaped hairs. Long,

slender taproot. Flattened, oval fruit pod with style at the

pod tip; up to 2,500 seeds per plant.

Habitat

Prefers dry, sandy and gravel,

nutrient poor soils with full sun.

Adapted to cold winters and hot, dry

summers.

Control

Reproduces by seed. Hand-pulling, digging and

herbicide.

Similar Species

Non-native:

Broad-leaved pepper-grass

(Lepidium

latifolium)

, stinkweed

(Thlaspi arvense)

, hoary cress

(

Lepidium

spp.)

Native:

Chickweed (

Stellaria

spp.), northern

bedstraw

(Galium boreale)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

102

Hoary Cress

(Lepidium appelianum

(globe-podded)

Lepidium draba

(heart-podded)

, Lepidium chalepense

(lens-

podded)

)

Native to western Asia, hoary cress (whitetop, peppergrass,

pepperweed) is a perennial in the Brassicaceae (Mustard) family.

There are 3 similar species listed under the

Weed Control Act

which can be differentiated by the

shape of the seed pod

Identication

Clusters of white flowers with 4 petals create a flat-topped umbel

appearance. Leaves blue-green to gray-green, alternate, covered

with soft white hairs, and lance-to-arrowhead-shaped; upper

leaves clasp the stem, lower leaves stalked. Stems up to 60 cm tall,

one to several stems per plant. Extensive, deep, creeping roots.

Seeds develop in pods;

the pod shape distinguishes the species

of hoary cress (see above)

. Up to 3,500 seeds.

Habitat

Requires full sun and

moderately moist to slightly dry

soils, but will tolerate alkaline soils.

Control

Reproduces by seed and creeping roots.

Mowing, cultivation, herbicide.

Similar Species

Non-native:

Other pepper-grass species (

Lepidium

spp.)

Native:

Common yarrow

(Achillea millefolium)

Isolated

WEED CONTROL ACT DESIGNATION:

NOXIOUS

103

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

104

Hogweed, Giant

(Heracleum mantegazzianum)

Native to Asia, giant hogweed (giant cow parsnip) is a

biennial in the Apiaceae (Carrot) family.

Use extreme

caution as this plant contains sap that is highly toxic and

can cause severe rashes, blisters, blindness and scarring.

Often confused with the native lookalike cow parsnip (which

has green stems, smaller height and leaves are not as deeply

lobed).

Identication

Large umbrella-shaped flower head with small, hairy,

5-petaled, white to pinkish flowers. Basal rosette produced

in first stage of growth, flowering stem in second. Leaves

alternate,

deeply lobed

, up to 100 cm wide with toothed

edges and coarse white hairs on the underside; lower leaves

compound with 3 leaflets. Stems are hollow, erect,

grows

up to 6 m tall

, covered with coarse hairs and

red to purple

spots

; leaf stems have similar spots. Stem and leaf stalks

covered with blisters containing

clear, harmful sap

. The sap

from both species can cause severe dermatitis. Large, deep

taproot. Flat, oval fruit capsule holds 1 flat seed with 2 wings;

up to 120,000 seeds per plant.

Habitat

Prefers disturbed, moist to wet soils with high organic

content and partial to full sun.

Not known to

be present

Control

Reproduces by seed and root buds. Remove seedlings

early, deadheading flowers and stump treatment. Herbicide

options exist.

Similar Species

Non-native:

None

Native:

cow parsnip

(Heracleum maximum)

, water hemlock

(Cicuta maculata)

, angelica (

Angelica

spp.)

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

105

Hound’s Tongue

(Cynoglossum officinale)

Native to Europe and Asia, hound’s tongue is a biennial in the

Boraginaceae (Borage) family. It contains toxic properties that

cause liver failure in animals.

Identication

Reddish-purple flowers

are small, funnel-shaped with 5 fused

petals and hang in small clusters from leaf axils. Basal rosette

produced in first stage of growth, flowering stem in second.

Leaves are oblong, distinctly veiny, up to 30 cm long, hairy on

both surfaces and shaped like a

dog’s tongue

. Stems grow to 1.5 m

tall, hairy and usually branched near top of plant. Deep, woody

taproot. Seeds are contained in

prickly 3-4 lobed, bur-like pods

Habitat

Prefers drier, well-drained sites,

but is tolerant of alkaline soils.

Control

Reproduces by seed. Mechanical control before seed,

biocontrol (hound’s tongue root weevil, Mogulones cruciger)

or herbicide.

Similar Species

Non-native:

Chinese hound’s tongue

(Cynoglossum amabile)

differentiated by blue flowers

Native:

Some native Symphyotrichum/Eurybia species may

have similar veined leaves prior to flowering

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

106

Iris, Pale Yellow

(Iris pseudacorus)

Native to Europe, pale yellow iris (yellow flag iris) is a

perennial in the Iridaceae (Iris) family. Buyer beware, this

plant may still be sold as an ornamental.

Identication

Large pale yellow to white flowers with 3 downward and 3

upward pointing petals, some petals with brown to purple

veins. Leaves are long, sword-like with pointed tip and

distinct raised midrib that is slightly off-centre

; emerge

from the ground in a fan-like arrangement. Stems 90-150 cm

tall; can be round or flattened. Thick and tuberous root

system that spreads by rhizomes and creeping roots. Seed

pods are large, three-sided, floating and 2-10 cm long.

Habitat

Prefers full sun to partial shade, but

can tolerate a range of soil acidity,

water depths and salinity.

Control

Reproduces by seed, rhizomes and creeping

roots. Digging.

Similar Species

Non-native:

Other iris species (

Iris

spp.)

Native:

Western blue flag iris

(Iris missouriensis)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

107

Jimsonweed

(Datura stramonium)

Origin is uncertain but sub-tropical, jimsonweed (devil’s

trumpet, devil’s cucumber, stinkwort, hell’s bells) is an annual

in the Solanaceae (Nightshade) family.

All parts of the plant

are toxic to humans and livestock.

Identication

White to pale purple

trumpet-shaped flowers

are 5-10 cm

with 5 pointed lobes sit singly on short stems. Leaves are

alternate with unevenly toothed edges, pointed tips, dark

green on the upper surface; long leaf stems up to 12 cm.

Flowers and leaves have a strong foul odor. Green to

reddish-

purple stems

are erect, hollow, extensively branched, 2 m tall.

Stout taproot with shallow, branched lateral roots. Fruit is

oval

shaped, covered with prominent spines

; up to 1,500 seeds

per plant.

Habitat

Prefers moist, nutrient-rich soils and

plenty of rain but can survive on less.

Control

Reproduces by seed. Hand-pulling and herbicide

if removed prior to seed set and sites revisited.

Similar Species

Other jimsonweed (

Datura

spp.) species

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

108

Knapweed, Bighead

(Centaurea macrocephala)

Native to Asia, bighead knapweed (Armenian basketflower,

golden thistle) is a perennial in the Asteraceae (Sunflower)

family.

Identication

One large yellow flower head per branch tip, 6 cm in

diameter. Bracts are fringed and thin with papery edges.

Leaves are alternate along entire stem, broad, hairy, lance-

shaped with pointed tips; leaf edges are slightly undulate

to smooth. Stems are several and erect, unbranched or

sparingly branched, growing 50-170 cm tall and covered

with long, soft and slightly cob-webby hairs. Woody taproot.

Habitat

Prefers moist well-drained soils with full sun and is drought

and frost tolerant.

Isolated

Control

Reproduces by seed and dividing the crown. Hand-pulling,

mowing or cultivation before seed set.

Similar Species

None – unique in appearance

WEED CONTROL ACT DESIGNATION:

NOXIOUS

109

Knapweed, Black

(Centaurea nigra)

Native to Europe, black knapweed is a perennial in the

Asteraceae (Sunflower) family.

Identication

One pink to purple flower head per branch tip, 3 cm in

diameter.

Comb-like bracts are black in the centre with

long fringes.

Basal leaves stalked, stem leaves stalkless and

decreasing in size upwards,

leaf edges are slightly toothed

or smooth

. Hairy stems branch mid-plant and 20-150 cm

tall. Woody taproot.

Habitat

Tolerant to a wide range of conditions.

Not known to

be present

Control

Reproduces by seed and regenerate from roots. Hand-pull,

mechanical control or herbicide before seed set.

Similar Species

Non-native:

Other knapweed species (

Centaurea

spp.)

Native:

None

WEED CONTROL ACT DESIGNATION:

NOXIOUS

110

Knapweed, Brown

(Centaurea jacea)

Native to Europe and Asia, brown knapweed is a perennial in

the Asteraceae (Sunflower) family.

Identication

One pink-purple-white flower head per branch tip, 2.5 cm

in diameter.

Bracts overlapping, brown and irregularly

torn.

Basal leaves up to 15 cm long, tapering at both ends.

Stem leaves lance-shaped, edges are shallowly-lobed

and stalkless.

Stems branching and 30-150 cm tall. Woody

taproot.

Habitat

Prefers cool, moist habitats.

Not known to

be present

Control

Reproduces by seed. Hand-pull, mechanical control or

herbicide before seed set.

Similar Species

Non-native:

Other knapweed species. Meadow knapweed is

a hybrid of black and brown knapweeds.

Native:

None

WEED CONTROL ACT DESIGNATION:

NOXIOUS

111

WEED CONTROL ACT DESIGNATION:

NOXIOUS

112

Knapweed, Diuse

(Centaurea diffusa)

Native to Eurasia, diffuse knapweed is an annual, biennial or

short-lived perennial in the Asteraceae (Sunflower) family.

Identication

One pink to white flower head per branch tip, 1.5 cm in

diameter.

Bracts are stiff, cream-yellow-light brown with

sharp rigid spines.

Basal rosette produced in first stage

of growth, flowering stem in second. Rosettes have finely

divided leaves with small hairs; mature leaves divided into

linear segments, alternate, broadly lance-shaped, grayish-

green, covered in woolly hairs.

Plants may be shorter than

other knapweeds, stems stiff, prickly and grey-green

in colour.

Stems grow to 60 cm tall and highly branched;

skeletons may tumble. Deep taproot. Up to 18,000 seeds

per plant.

Habitat

Thrives in semi-arid and arid environments with light, porous

soils such as gravelly loam, and loamy sands. It is not tolerant

of moist soils, flooding or shade.

Regionally

common

Control

Reproduces by seed. Repeated hand-pulling and removal

of all plant parts over several years on small infestations,

biocontrol (the seed head weevil,

Larinus minutus

, and the

root weevil,

Cyphocleonus achates

) or herbicide.

Similar Species

Non-native:

Spotted knapweed

(Centaurea stoebe)

hybrid knapweed

(Centaurea × psammogena)

Native:

None

WEED CONTROL ACT DESIGNATION:

NOXIOUS

113

Knapweed, Hybrid

(Centaurea × psammogena)

As a hybrid cross between spotted knapweed and diffuse

knapweed, hybrid knapweed is a biennial or short-lived

perennial in the Asteraceae (Sunflower) family.

Identication

One purple to white flower head per branch tip. Bracts have

a dark tip (similar to spotted knapweed) and long bristles

on the edges (similar to diffuse knapweed). Basal rosette

produced in first stage of growth, flowering stem in second.

Leaves finely divided, covered with fine hairs. Stems grow to

20-80 cm tall, heavily branched. Woody taproot.

Habitat

Thrives in sandy, coarse, well-drained soils in full sun.

Not known to

be present

Control

Reproduces by seed. Hand-pulling before seed set.

Similar Species

Non-native:

Other knapweed species (

Centaurea

spp.)

Native:

None

WEED CONTROL ACT DESIGNATION:

NOXIOUS

114

Knapweed, Meadow

(Centaurea × gerstlaueri)

Native to Eurasia, as a hybrid cross between brown and

black knapweed, meadow knapweed is a perennial in the

Asteraceae (Sunflower) family.

Identication

One pink to purple flower head at the ends

of upper branches. Comb-like bracts below flowers are

overlapping,

fringes on bracts are as long or longer than

the width of the bract. Can resemble either brown or black

knapweed with light or dark brown to black bracts, but has

a distinctive cooper-gold sheen on bracts when in bloom

Basal leaves stalked, up to 15 cm long, stem leaves stalkless.

Leaf edges are slightly toothed or irregularly pinnately lobed.

Stems branch mid-plant and are 30-150 cm tall; several

stems. Deep taproot.

Habitat

Prefers habitats with

sufficient moisture.

Control

Reproduces by seed. Hand-pull,

mechanical control before seed set.

Similar Species

Non-native:

Other knapweed species especially brown

knapweed or black knapweed, distinguished by differences

in the bracts. May also be confused with Canada thistle

(Cirsium arvense)

Native:

None

Not known to

be present

WEED CONTROL ACT DESIGNATION:

NOXIOUS

115

Knapweed, Russian

(Rhaponticum repens)

Native to Eurasia, Russian knapweed is a perennial in the

Asteraceae (Sunflower) family. It is classified under its own

genus compared to other knapweeds. It can cause chewing

disease in horses.

Identication

One purple to pink flower head per branch tip,

1-2 cm in diameter.

Bracts are rounded with papery edges

and no noticeable fringes or spines.

Lower leaves up to 15 cm

and deeply lobed; upper leaves are sometimes toothed, narrow,

unlobed and significantly shorter. Young plants are covered in

cobwebby hairs. Stems branching and up to 1 m tall. Creeping

roots with black or dark brown scales; colony forming. Up to

1,200 seeds per plant.

Habitat

Thrives in a wide range of

soil conditions, but does very well

in clay soil. It is intolerant of shade,

prolonged drought,

and wet sites.

Control

Reproduces by seed. Hand-pull,

mechanical control or herbicide before seed set.

Similar Species

Non-native:

Other knapweed species (

Centaurea

spp.)

Native:

None

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

116

Knapweed, Spoed

(Centaurea stoebe

subsp.

australis)

Native to Europe, spotted knapweed is a perennial in the

Asteraceae (Sunflower) family.

Identication

One pink to purple flower head per branch tip, 4 cm in diameter.

Bracts have distinctive dark fringed edges, giving a ‘spotted’

appearance.

Rosette leaves are deeply lobed,

grayish green

up to 15 cm long. Stem leaves are alternate and finely divided

into linear segments. Stems up to 120 cm tall, highly branched.

Strong taproot. Up to 140,000 seeds per plant.

Habitat

Well-drained, light to coarse-textured soils in full sun.

Widespread

Control

Reproduces by seed. Hand-pull, mechanical control, biocontrol

(the seed-head weevil,

Larinus minutus

, and the root-mining

weevil,

Cyphocleonus achates

) or herbicide before seed set.

Similar Species

Non-native:

Other knapweed species (

Centaurea

spp.)

Native:

None

WEED CONTROL ACT DESIGNATION:

NOXIOUS

117

Knapweed, Squarrose

(Centaurea virgata

subsp.

squarrosa)

Native to the eastern Mediterranean and Asia, squarrose

knapweed is a perennial in the Asteraceae (Sunflower) family.

Identication

One pink to pale purple flower head per branch

tip, 1 cm in diameter, up to 100 flower heads per plant;

smaller than other knapweeds. Bracts are strongly curved

backward at tip

and longer than spines at sides, pale green

to tan coloured, sometimes purple-tinged; 4-6 pairs of lateral

spines. Basal and lower leaves are deeply divided, minutely

resin-gland-dotted and green-grey colour; leaves decrease in

size moving up the stem and appear bract-like or lack stalks.

Stems are rough, covered in fine hairs with resin dots, highly

branched and grow up to 50 cm. Strong taproot.

Habitat

Prefers coarse, well drained

soils on sites with cold winters and dry,

hot summers. It is tolerant of alkaline

soils and summer drought.

Control

Reproduces by seed. Hand-pulling

and mechanical control before seed set.

Similar Species

Non-native:

Other knapweed species (

Centaurea

spp.),

Canada thistle

(Cirsium arvense)

Native:

None

Not known to

be present

WEED CONTROL ACT DESIGNATION:

NOXIOUS

118

Knapweed, Tyrol

(Centaurea nigrescens)

Native to western Asia and southwestern Europe, Tyrol

knapweed is a perennial in the Asteraceae (Sunflower)

family.

Identication

One pink to purple flower head per branch tip, 3 cm in

diameter; outer ring of individual flowers are longer than

inner individual flowers.

Bracts are long, slender with dark

brown triangular fringed tips.

Basal leaves oblong to lance-

shaped; upper leaves smaller with few lobes;

larger leaves

than most knapweed species

. Stem single to branched,

rough, covered with fine cobwebby hairs and grow up to

150 cm. Woody taproot.

Habitat

Prefers sandy, loamy or coarse, well drained soils.

Not known to

be present

Control

Reproduces by seed. Hand-pull or mechanical control

before seed set.

Similar Species

Non-native:

Other knapweed species (

Centaurea

spp.)

Native:

Wild bergamot

(Monarda fistulosa)

WEED CONTROL ACT DESIGNATION:

NOXIOUS

119

Knotweed, Giant

(Reynoutria sachalinensis)

Native to northern Japan, giant knotweed is a perennial in the

Polygonaceae (Buckwheat/Smartweed) family. This plant is

the largest of the knotweeds and root growth can damage

infrastructure.

Identication

Small greenish-white flowers occur in showy branched clusters.

Leaves are

heart shaped at the base

and 20-40 cm long,

generally 2x the size of other knotweed leaves

; underside

hairy.

Bamboo-like stems

are hollow and smooth with swollen

nodes, 3.5 m or taller, base surrounded by a membranous

sheath and can grow 4-5 cm per day. Creeping roots.

Habitat

Tolerant of a wide range of habitats but requires moisture. It

can withstand temperatures of –40°C.

Not known to

be present

Control

Reproduces by seeds and creeping roots. Cutting and

herbicide.

Similar Species

Non-native:

Other knotweed species (

Fallopia

and

Persicaria

spp.)

Native:

None

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

120

Knotweed, Himalayan

(Persicaria wallichii

formerly

Polygonum polystachyum)

Native to Asia, Himalayan knotweed (Kasmir plume, bell-

shaped knotweed) is a perennial in the Polygonaceae

(Buckwheat) family.

Identication

Small

pink

to white flowers occurs in loose clusters on reddish

stalks. Leaves are broadly

lance-shaped with long pointed

tips

and hairs on the edges and underside. Bamboo-like stems

are hollow,

slightly hairy

, reddish, branched in the upper half

with swollen nodes, up to 3 m tall. Creeping roots. Papery

fringed fruit capsule holds smooth, shiny, black seeds.

Habitat

Prefers full sun and moist soils (loamy, silty or sandy).

Not known to

be present

Control

Reproduces by seed and creeping roots. Repeated grazing

and digging over several growing seasons but requires

removal of all fragments or herbicide.

Similar Species

Non-native:

Other knotweed species (

Fallopia

spp.)

Native:

None

WEED CONTROL ACT DESIGNATION:

UNREGULATED

121

Knotweed, Hybrid

(Reynoutria × bohemica)

As a hybrid cross between Japanese knotweed and giant

knotweed, hybrid knotweed (Bohemian knotweed)

may have

characteristics of both

and can hybridize with either. It is a

perennial in the Polygonaceae (Buckwheat/Smartweed) family.

Identication

Small, creamy to greenish-white flowers occur in showy

plume-like, branched clusters. Leaves are alternate, variably

oval-shaped, 5-30 cm long; underside hairy.

Bamboo-like

stems

are hollow and smooth with swollen notes, 2.5-3 m tall,

base surrounded by a membranous sheath. Creeping roots.

Fruits are white and heart-shaped.

Habitat

Requires sufficient moisture and tolerant to a variety of soil

conditions.

Isolated

Control

Reproduces by seeds and creeping roots. Cutting and

herbicide.

Similar Species

Non-native:

Other knotweed species (

Fallopia

and

Persicaria

spp.)

Native:

None

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

122

Knotweed, Japanese

(Reynoutria japonica)

Native to Asia, Japanese knotweed is a perennial in the

Polygonaceae (Buckwheat/Smartweed) family. Root growth

can damage infrastructure.

Identication

Small creamy white to greenish-white flowers are small

occur in showy plume-like branched clusters. Leaves

alternate, stalked, ovate with

a truncated base

, 3-10 cm

long with pointed tips.

Bamboo-like stems

are hollow and

smooth with swollen nodes, 1-3 m tall, base surrounded by

a membranous sheath. Robust creeping root system; can

reproduce from a single fragment. White fruit with small,

black seeds within; up to 200,000 seeds per plant.

Habitat

Prefers open areas but can grow

in shade and requires sufficient

moisture.

Control

Reproduces by seeds and creeping roots. Hand-pulling,

grazing, mowing, cutting and herbicide.

Similar Species

Non-native:

Other knotweed species (

Fallopia

and

Persicaria

spp.)

Native:

None

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

123

WEED CONTROL ACT DESIGNATION:

UNREGULATED

124

Kochia

(Bassia scoparia)

Native to Europe and Asia, kochia is an annual forb in the

Amaranthaceae (Amaranth) family. Herbicide resistance

makes it difficult to control.

Identication

Small clusters of very small green flowers about 3mm across

in short, dense spikes. Stems are erect, green to reddish

tinged, with many

branches curving upwards to create a

bushy to pyramid shape from 6 inches to 6 feet in height

These bushes

can form tumbleweeds

, spreading their seeds

far distances. Leaves are alternate, simple and linear to

narrowly oval, 1.5-6 cm long, surfaces are hairless to sparsely

hairy, undersides hairy

with 1-5 prominent veins

. Deep

taproots.

Habitat

Prefers arid and semi-arid regions,

but tolerant of a wide range of habitats,

including saline soils.

Control

Reproduces by seed. Hand pulling or mowing before

seed set, planting competitive crops, or herbicide. Some

herbicide resistance.

Similar Species

Non-native:

Five-hooked bassia (

Bassia hyssopifolia

) have a

long-hooked structure on each sepal (not known to be present

in Alberta

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

125

Loosestrife, Purple

(Lythrum salicaria)

Native to Europe, Asia and Africa, purple loosestrife is a perennial

in the Lythraceae (Loosestrife) family.

Identication

Pink to purple

flowers with 5-7 petals

are clustered

on a tall, vertical spike extending 5-90 cm; one or more flowering

spikes per plant. Leaves are clasping, lance-shaped with notched

base and smooth edges; slightly hairy,

occurring opposite or

whorled on the stem

. Stems up to 2.5 m tall,

mostly square

and

woody. Extensive root system of creeping roots and taproot,

clump forming. Seed pods are small brown capsules; up to 2-3

million seeds per plant, viable up to 20 years.

Habitat

Thrives in areas with moist, nutrient-rich soils, but has low

nutrient requirements and can tolerate shallow flooding and partial

shade.

Isolated

Control

Reproduces by seed and creeping roots. Repeated

hand-pulling, biocontrol (two defoliators,

Galerucella

calmariensis

and

G. pusilla

, and one root-mining weevil,

Hylobius

transversovittatus

), or herbicide.

Similar Species

Non-native:

Dame’s rocket

(Hesperis matronalis),

European wand

loosestrife

(Lythrum virgatum)

Native:

Common fireweed

(Chamerion angustifolium)

dwarf fireweed

(Epilobium latifolium)

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

126

Medusahead

(Taeniatherum caput-medusae)

Native to the Mediterranean, medusahead is a winter annual

in the Poaceae (Grass) family.

Identication

Flowering spikes are 1-5 cm and occur in pairs. Bracts at the

spike base have long, stiff and finely barbed awns up to 7 cm

long. Awns are straight when green, becoming twisted after

drying. Leaf blades are narrow, sometimes hairy and 3-6 cm

long; short auricles and membranous ligule are present.

Stems are hairy, decumbent to erect and grow up to 50 cm

tall. Deep fibrous root system. Seeds are gold to brown, will

twist as they mature and produce up to 7 seeds per spike.

Habitat

Prefers climates with mild to cold

winters and hot summers, and fine

textured or clay soils.

Control

Reproduces by seed. Hand-pulling, mowing, early grazing

and cultivation.

Similar Species

Non-native:

None

Native:

Squirrel tail

(Elymus elymoides)

, fox tail barley

(Hordeum jubatum)

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

127

Mullein, Common

(Verbascum thapsus)

Native to Europe, common mullein (candlestick plant, velvet

dock or cowboy toilet paper (not advised!)) is a biennial in

the Scrophulariaceae (Figwort/Snapdragon) family. It has

been used as a piscicide to control fish.

Identication

Small, yellow 5-petaled flowers arranged on tall spikes. Basal

rosette produced in first stage of growth, flowering stem

in second. Large leaves are soft and felt-like on upper and

lower surfaces, alternately arranged on the stem; basal and

rosette leaves larger. Stems can become woody and grow

up to 2.5 m tall. Deep taproot. Tiny seeds found within hairy

capsules arranged densely along the top of the flowering

stalk; up to 300,000 seeds per plant.

Habitat

Prefers well-drained, sandy or gravelly soils,

but is intolerant of shades.

Control

Reproduces by seed. Hand-pulling entire plant

before seed set or herbicide in rosette stage.

Similar Species

Non-native:

Moth mullein

(Verbascum blattaria)

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

128

Nutsedge, Yellow

(Cyperus esculentus)

Native to sub-tropical North America, yellow nutsedge is a

perennial in the Cyperaceae (Sedge) family.

Identication

Umbrella-shaped clusters of straw-coloured or golden-

yellow flower heads. Narrow leaves are alternate, mostly

basal, grass-like, waxy, prominent midrib, 20–90 cm long and

bright green to yellow-green colour. Stems are unbranched,

triangular in cross section and up to 75 cm tall. Fibrous roots

with woody, brown striped tubers; one tuber can produce

hundreds of shoots per growing season. Up to 90,000 seeds

per plant.

Habitat

Prefers wet habitats and can become troublesome in low-

lying irrigated soils that remain wet.

Not known to

be present

Control

Reproduces by seed and tubers that form on short rhizomes.

Hand-pulling and herbicide.

Similar Species

Non-native:

None

Native:

Native sedges (

Carex

spp.)

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

129

Pepper-Grass, Broad-Leaved

(Lepidium

latifolium)

Native to Europe and West Asia, broad-leaved pepper-grass

(perennial pepperweed, tall whitetop, giant whiteweed, ironweed)

is a creeping perennial in the Brassicaeae (Mustard) family.

Identication

Small, white flowers with 4 petals, < 1 cm wide occur on

rounded clusters at the branch ends. Leaves are bright-to-

gray-green, alternate, taper to a pointed tip with

prominent

whitish midvein

. Basal leaves are waxy up to 30 cm long with

long stalks; stem leaves are smaller with shorter stalks. Stems

up to 1.5 m tall, branched. Deep spreading roots account for

up to 40% of the plant’s biomass. Seed pods are flat, rounded,

2-3 mm long; many pods per plant and 2 seeds per pod.

Habitat

Thrives in moist sandy soils

and tolerant to saline soils.

Control

Reproduces by seed and creeping roots.

Hand-pulling, digging and herbicide.

Similar Species

Non-native:

Hoary cress (

Lepidium appelianum

(globe-podded),

L. draba

(heart-podded),

L. chalepense

(lens-podded))

Native:

Native pepper-grass (

Lepidium

spp.) distinguished by

smaller size

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

130

Persian Darnel

(Lolium persicum)

Native to central Asia, Persian darnel is an annual or winter

annual in the Poa (Grass) family. It is easily misidentified as a

grain or cereal crop.

Identication

Spike is straight, 10-20 cm long; each flattened

spikelet is 1-2 cm long spaced their own length apart. Seed

heads consist of alternating spikelets, each containing 5-7

seeds. Leaves are flat, 6-15 cm long by 2-8 mm wide, dark

green; auricles may be absent or measure up to 2 mm and

truncated ligules are 0.5-2 mm. Upper leaf is slightly rough and

undersides are smooth. Stem is erect, branching, 20-70 cm tall

with 3-4 nodes and rough below flower head with

red tinge at

stem base

. Fibrous root system.

Habitat

Prefers relatively dry soil.

Control

Reproduces by seed. Since seedlings

emerge early, a primary shallow tilling in early spring will

promote the weed’s germination, then a shallow tilling of

weed seedlings once most have emerged but could delay

crop planting. Herbicides are most effective if applied when

the weeds have 1 – 4 leaves.

Similar Species

Non-native:

Downy brome

(Bromus tectorum)

, perennial

ryegrass

(Lolium perenne)

Native:

Native grasses

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

131

Phragmities, Invasive

(Phragmites australis

ssp.

australis)

Native to Europe, invasive Phragmites is a tall, aquatic or semi-

aquatic perennial in the Poaceae (Grass) family.

Identication

Flowers first appear dark purple, turning tan/brown as they

develop, large, feathery plumes that droop, 15-50 cm long.

Leaves

are blue-green

, alternate and 25-50 cm long without hairs. Stems

are tall,

up to 6 m, hollow with many nodes

. Roots are extensive

and primarily responsible for reproduction.

Habitat

Prefers still or slow-moving waters, typically

up to 1 m deep, but tolerates a wide range of

conditions.

Control

Reproduces primarily by creeping roots. Mechanically remove/

damage all roots, hand-pulling, herbicide, fire, flooding may be

effective.

Similar Species

Non-native:

Canary reedgrass (

Phalaris arundinacea

) (native

and introduced forms) is much shorter (1.5 m) with compact and

narrow (sike-like) flower/seed heads.

Native:

Native phragmites (

Phragmites australis

ssp.

americanus

)

can be distinguished by its less aggressive growth habits, intense

red-purple coloring in the lower stems, sparse seed head, black

spots may be found in the fall, and the leaves do not persist after

winter.

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

132

Puncturevine

(Tribulus terrestris)

Native to the Mediterranean and Africa, puncturevine is an

annual in the Zygophyllaceae (Caltrop) family. The sharp

spines can cause foot and digestive tract injuries in grazing

animals, and the plant contains poisons that can harm humans.

Identication

Single yellow flowers with 5 petals, 4-10 mm wide sit on

short stalks between each pair of leaves. Opposite leaves are

hairy and pinnately compound with 8-16 leaflets. Reddish

stems are branched from the root, hairy and usually lie along

the ground; can be 10 cm to over 1 m long. Woody taproot

up to 2.5 m deep. Fruit is a woody, hard pod that splits into

4-5 nutlets; up to 500 seeds/nutlets.

Nutlets resemble bull

heads with 2-4 sharp spines up to 10 mm long.

Habitat

Tolerant of a wide range of habitats

but prefers dry, loose, sandy soils.

Control

Reproduces by seed. Hand-pulling and

shallow cultivation.

Similar Species

Non-native:

Leaves similar to cicer milkvetch

(Astragalus cicer)

before flowering

Native:

None

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

133

Queen Anne’s Lace

(Daucus carota)

Native to Eurasia, queen Anne’s lace is a biennial in the

Apiaceae (Carrot) family.

Identication

Clusters of white umbel shaped flower heads are 5-10 cm

on long hairy stalks;

long, 3-pronged, finger-like bracts

surround flower head base.

At maturity, bracts curl up

encompassing seeds in nest-like shape

. Basal rosette

produced in first stage of growth, flowering stem in second.

Leaves pinnately compound, finely divided (carrot-like).

Lower leaves stalked; upper leaves stalkless. Stems are erect,

smooth with minimal branching, up to 1 m tall and covered

with stiff, white hairs.

Habitat

Tolerant of a variety of soil

types in full sun.

Control

Reproduces by seed. Hand-pulling before seed set for small

infestations, mowing multiple times a season for several

years, or herbicide.

Similar Species

Non-native:

Wild caraway

(Carum carvi)

Native:

Species in the Apiaceae (Carrot) family, common

yarrow

(Achillea millefolium)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

134

Ragwort, Tansy

(Jacobaea vulgaris)

Native to Eurasia, tansy ragwort (stinking Willie) is a biennial

or short-lived perennial in the Asteraceae (Sunflower) family.

It is toxic to livestock and humans.

Identication

Flat-topped clusters of yellow daisy-like flowers with 13 ray

petals surround a yellow centre on stem ends. Black-tipped

bracts below the flower in a single row visible before bloom.

Basal rosette produced in first stage of growth, flowering

stem in second. Rosettes with 10-20 leaves with web-like

hairs; stem leaves alternate, decreasing in size upwards.

Leaves deeply indented with blunt-toothed lobes giving a

ruffled appearance; leaf underside is somewhat hairy. Several

or solitary stems, may be branched and up to 180 cm. Stems

and leaf stalks often purplish with cobwebby hairs. Deep

taproot. Up to 150,000 seeds per plant.

Habitat

Prefers dry areas with full

sun to partial shade and well

drained soils.

Control

Reproduces by seed. Hand-pulling and herbicide.

Similar Species

Non-native:

Common groundsel

(Senecio vulgaris)

Native:

Ragwort and groundsel species (

Senecio

spp.)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

135

Rush Skeletonweed

(Chondrilla juncea)

Native to the Mediterranean, Asia and North Africa, rush

skeletonweed (nakedweed, devils’ grass) is a short-lived

perennial in the Asteraceae (Sunflower) family.

Identication

Single or clusters of 2-5 yellow flowers are scattered on

stems and branch tips. Rosette leaves deeply toothed but

wither as stem bolts, stem leaves are narrow; produce milky

sap when damaged. Mass of wiry stems can grow up to 1.2 m

tall;

covered with downward bent, bristly hairs on the lower

10-15 cm of stem

. Slender taproot up to 2 m deep. Up to

20,000 seeds per plant.

Habitat

Thrives in coarse and well-drained soils and areas of full sun

without an extended summer drought.

Not known to

be present

Control

Reproduces by seed. Hand-pulling, grazing and herbicide.

Similar Species

Non-native:

None

Native:

Wire lettuce

(Stephanomeria pauciflora)

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

136

Russian Olive

(Elaeagnus angustifolia)

Native to southern Europe, Russian olive is a deciduous

shrub/tree in the Eleagnaceae (Oleaster) family.

Identication

Small creamy-yellow flowers occur in clusters. Leaves are

2-10 cm long, alternate, egg to lance-shaped,

silvery-green

with smooth edges on current year twigs. Branches flexible

and

thorny

. Stems, buds and leaves are densely covered with

silvery to rusty scales. Bark is thin and brown, developing

shallow cracks, then peeling in long strips; up to 9-15 m tall

with a dense, rounded crown. Fruits are a silvery, oval-shaped,

1-2 cm long, enclosing a single 6-13 mm seed.

Habitat

Prefers well-drained soils in full

sun to part shade. Tolerant to wide

variety of soils and wind, heat and

saline conditions. Thrives in southeastern

parts of the province.

Control

Reproduces by seed. Mechanical control (cutting, mowing)

alone will enable resprouting, however when combined with

herbicides can be effective.

Similar Species

Non-native:

Autumn olive

(Elaeagnus umbellata)

Native:

Silverberry

(Elaeagnus commutata)

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

137

Saltcedar/Tamarisk

(Tamarix

spp.

)

Native to Asia, saltcedar/tamarisk is a deciduous shrub or

small tree in the Tamaricaceae (Tamarisk) family. There are

three species listed in Alberta: Chinese tamarisk

(Tamarix

chinensis)

, smallflower tamarisk

(T. parviflora)

and saltcedar

(T. ramosissima)

. Buyer beware, this plant may still be sold as

an ornamental under the common names, pink cascade and

summer glow.

Identication

Flowers are small, pink to white, with 4-5 petals borne in

finger-like clusters. Leaves are alternate, small, overlapping,

and appear

scale-like; resembles cedar foliage

. Leaves

turn yellow-orange in autumn. Stems up to 8 m tall, highly

branched with smooth, dark brown to reddish brown bark.

Deep taproot and roots that can form from non-root tissue.

Habitat

Tolerant of many habitat types but

is shade intolerant and prefers fine-

textured soils.

Control

Reproduces by seed and creeping roots. Repeated hand-

pulling and cutting.

Similar Species

None – unique in appearance

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

138

Saltlover

(Halogeton glomeratus)

Native to Eurasia, saltlover (halogeton, barila) is a summer or

winter annual in the Chenopdiaceae (Goosefoot) family. It is

highly poisonous to livestock.

Identication

Two types of flowers with 5 sepals - smaller flowers have

toothed sepals and larger flowers are 2-3 mm wide – both

occur in leaf axils, are light yellow-green with a pink centre.

Leaves are alternate, simple, small, fleshy, tubular, blue-

green with

a small bristle at the end of each leaf

. Red stems

turn yellow-white at maturity and 8-30 cm tall, succulent

and branched from the base. Taproot up to 0.5 m deep. Up

to 50,000 seeds per plant.

Habitat

Tolerant of semi-arid environments, saline and alkaline soils.

Isolated

Control

Reproduces by seed. Mechanical and herbicide control.

Similar Species

Non-native:

Kochia

(Bassia scoparia

) before flowering,

Russian thistle

(Salsola pestifera)

Native:

None

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

139

Scabious, Field

(Knautia arvensis)

Native to Europe, field scabious (blue buttons, bachelor’s

buttons) is a long-lived perennial in the Dipsacaceae

(Teasel) family.

Identication

One pink-blue-purple flower head per branch tip, 4 cm in

diameter; ring of narrow green bracts below flower head.

Leaves are hairy and highly variable in the degree of the

lobes. Lower leaves are up to 25 cm long but become

smaller higher on plant; stem leaves are opposite and attach

directly to stem. Stems up to 1.5 m, hairy with one or several

branching stems. Deep taproot. Seed head is dome-like and

covered in bristly hairs.

Habitat

Prefers nutrient-rich and

moderately dry soils but can

also establish in gravelly soils.

Control

Reproduces by seed. Herbicide, cultivation or mechanical

removal of the seed heads/top growth.

Similar Species

Non-native:

Pincushion flower

(Scabiosa columbaria)

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

140

Sow Thistle, Perennial

(Sonchus arvensis)

Native to Europe and Asia, perennial sow thistle (creeping

sow thistle, field milk thistle, marsh sow thistle) is a perennial

in the Asteraceae (Sunflower) family.

Identication

Yellow dandelion-like flowers in loose clusters at the ends

of stems; bracts are often covered with sticky hairs.

Leaves

are alternate, weakly prickled edges with variable shape.

Stems 30-150 cm tall, upright, hollow, branched at the top

portion of the plant;

contain a milky sap

. Creeping roots

up to 3 m deep and fragile. Small, dandelion-like seeds with

wings; up to 13,000 seeds per plant.

Habitat

Adapted to a wide range of conditions but does best in

moist, fertile soils with full sunlight.

Control

Reproduces by seed and creeping roots. Hand-pulling,

cultivation or mowing with regular repetition or herbicide.

Similar Species

Non-native:

Annual sow thistle

(Sonchus oleraceus)

, narrow

leaved hawksbeard

(Crepis tectorum)

Native:

None

Widespread

WEED CONTROL ACT DESIGNATION:

UNREGULATED

141

Spurge, Leafy

(Euphorbia virgata

formerly

Euphorbia esula)

Native to Asia and Europe, leafy spurge is a perennial in the

Euphorbiaceae (Spurge) family. It is toxic to humans, livestock

and wildlife when consumed or when milky sap contacts skin.

Identication

Clusters of small, yellowish-green flowers lack

petals and sepals and are supported by 2 heart-shaped,

leafy bracts. Leaves are alternate, oblong, narrow, waxy and

attached directly to the stem.

Leaves and stems contain

a white milky sap.

Stems up to 90 cm tall, smooth and

arranged in clumps. Deep and extensive creeping roots with

pink buds on lateral roots. Small seeds grow in pods on top

of bracts which explode upon maturity to launch seeds up to

5 m; up to 130,000 seeds per plant.

Habitat

Tolerates a wide variety

of conditions but prefers warm

climates and full sun.

Control

Reproduces by seed and creeping

roots. Targeted grazing by sheep and goats,

biocontrol (leafy spurge beetles,

Aphthona

spp.) or

herbicide, especially when used together.

Similar Species

Non-native:

Yellow toadflax

(Linaria vulgaris)

before

flowering, but no milky sap; cypress spurge

(Euphorbia

cyparissias)

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

142

St John’s-Wort, Common

(Hypericum perforatum)

Native to Eurasia and North Africa, common St John’s-wort

is a perennial in the Clusiaceae (St John’s-wort) family. It has

been widely cultivated as a medicinal plant and may be toxic to

livestock.

Identication

Numerous yellow 5-petaled flowers up to 2.5 cm

in diameter form flat-topped clusters;

distinctive black glands

along petal edges

. Leaves are opposite, oval-shaped to 2.5 cm

long, lack stalks, darker green above with tiny transparent dots

on the leaf surface. Stems 30-90 cm tall, erect, green to reddish

with black dots, branching near the top. Extensive taproot and

lateral roots. Three-pointed capsule 5 mm long and contain

numerous rust-coloured seeds; up to 35,000 seeds per year.

Habitat

Prefers well-drained,

coarse textured soils and

temperate climates, but can

tolerate a wide variety of conditions.

Control

Reproduces by seed and creeping roots.

Herbicide, mechanical and re-seeding with perennial grasses

or legumes.

Similar Species

Non-native:

Tansy ragwort

(Jacobaea vulgaris)

Native:

Western St John’s-wort (

Hypericum scouleri

subsp.

nortoniae

)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

143

Starthistle, Yellow

(Centaurea solstitialis)

Native to the Mediterranean and North Africa, yellow

starthistle (yellow cockspur, golden starthistle) is a winter

annual in the Asteraceae (Sunflower) family. It can cause

chewing disease in horses.

Identication

One yellow flower head per branch tip. Sharp straw-coloured

spines up to 2 cm long radiate from the individual bracts.

Lower leaves deeply lobed, upper leaves smaller towards the

top of the plant and covered with cottony hairs. Rigid stems

up to 2 m tall, branched, covered with hairs. Taproot up to

1 m deep. Up to 150,000 seeds per plant.

Habitat

Shade intolerant, but can thrive in periods of drought, rocky,

shallow soils and areas of full sun.

Not known to

be present

Control

Reproduces by seed. Hand-pulling, cultivation, mowing or

herbicide before seed set.

Similar Species

Non-native:

Bighead knapweed

(Centaurea macrocephala)

Maltese starthistle

(Centaurea melitensis)

Native:

None

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

144

Swallowwort, Black

(Vincetoxicum nigrum)

Native to northern and southwestern Europe, black

swallowwort is a perennial in the Apocynaceae (Dogbane)

family. Also known as black dog-strangling vine.

Identication

Dark purple flowers

in clusters of 6-10 on

short stems.

Leaves are oval, shiny, dark green

, 7.5-10 cm

with smooth margins on short leaf stalks. Stems are green,

unbranching vines that may be erect or twisting, contains

clear sap, and grow 0.6-2 m long. Extensive rhizomatous

roots.

Habitat

Found in many soil

types and moisture conditions,

including full sun to dense

shade. Grows by climbing other vegetation

and creating tangled thickets.

Control

Reproduces by seed and roots. Hand-pulling may be

effective for small populations, watch for resprouting. Mowing

may prevent seed production.

Similar Species

Non-native:

Pale swallowwort (

Vincetoxicum rossicum

) has

lighter green and looser-looking flowers

Native:

Purple clematis (

Clematis occidentalis

) has large,

showy purple flowers

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

145

Swallowwort, Pale/European

(Vincetoxicum

rossicum)

Native to northern and southwestern Europe, pale/European

swallowwort is a perennial in the Apocynaceae (Dogbane)

family. Also known as pale dog-strangling vine.

Identication

Pale pink to maroon or reddish-brown flowers

form loose clusters of 6-10 on short stems. Leaves are oval,

shiny, dark green, 7.5-10 cm with smooth margins on short

leaf stalks. Stems are green, unbranching vines that may

be erect or twisting, contains clear sap, and grow 0.6-2 m.

Extensive rhizomatous roots.

Habitat

Adapted to many soil

types and moisture conditions.

Grows by climbing other vegetation and

creating tangled thickets.

Control

Reproduces by seed and roots.

Hand-pulling may be effective for small populations, watch for

resprouting. Mowing may prevent seed production.

Similar Species

Non-native:

Black swallowwort (

Vincetoxicum nigrum

) has

dark purple and tighter-looking flowers

Native:

Purple clematis (

Clematis occidentalis

) has large,

showy purple flowers

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED N OXIOUS

146

Tansy, Common

(Tanacetum vulgare)

Native to Europe, common tansy is a perennial in the

Asteraceae (Sunflower) family. It is mildly toxic to humans

and wildlife if consumed.

Identication

Yellow-orange,

button-like flower

heads form flat-topped,

dense clusters of 20-100 at stem ends. Leaves are alternate,

deeply divided into leaflets with toothed edges (fern-like)

and has a strong odour. Stems often purplish-red, woody

and grow up to 180 cm tall. Woody, creeping roots. Up to

50,000 seeds per plant.

Habitat

Prefers well-drained soils and full sun.

Control

Reproduces by seed and creeping roots. Cutting, mowing

and herbicide.

Similar Species

Non-native:

Tansy ragwort

(Jacobaea vulgaris)

Native:

Dune tansy

(Tanacetum bipinnatum)

Widespread

WEED CONTROL ACT DESIGNATION:

NOXIOUS

147

COMMON TEASEL

CUT-LEAF TEASEL

WEED CONTROL ACT DESIGNATION:

UNREGULATED

148

Teasel, Common

(Dipsacus fullonum)

Teasel, Cut-Leaf

(Dipsacus laciniatus)

Native to Eurasia and northern Africa, common teasel and

cut leaf teasel are biennials to short-lived perennial forb in

the Caprifoliaceae (Honeysuckle) family.

Identication

Common teasel has light purple to lavender flowers

, while

cut-leaf teasel has white flowers

, both forming dense

bands around oval, spiny flower heads that bloom from

early to late summer. The flower heads are surrounded by

stiff, spiny bracts that curve upward (common teasel) and

downward for cut-leaf.

Leaves differ: common teasel has long, narrow leaves with

smooth or slightly wavy edges, while cut-leaf teasel leaves

are deeply cut, lobed, and jagged.

Both species have

opposite leaves that join to form a

water-holding cup

; stems are tall, stiff, ridged, and

covered

in small prickles

, often branching near the top. Plants form a

low rosette in the first year, followed by a tall flowering stalk

in the second year (2–2.5 m tall). Produces many small seeds

that persist into winter.

Habitat

Often found along field edges, in

roadside ditches, and in disturbed areas

such as waste ground and pastures.

Control

Reproduces by seed. Herbicide or hand-pull, removing as

much of the taproot as possible.

Similar Species

None – unique in appearance

Not known to

be present

WEED CONTROL ACT DESIGNATION:

UNREGULATED

149

Thesium, Field

(Thesium ramosum)

Native to China and central Europe, thesium is a perennial

in the Santalaceae (Sandalwood) family.

Identication

Tiny

, white to greenish-white flowers with

5 triangular

petals surrounding 5 yellow stamens

and 1 anther, 4-5 mm

in diameter.

Leaves very narrow

, 3-4 cm long, 4 mm wide,

pale green, lance- to sickle-shaped, smooth edges. Stems

are erect or ascending, highly branched, 20-25 cm tall.

Thick taproot with some branching.

Inconspicuous unless

in bloom.

Habitat

Commonly found in open habitats. Tolerates a range of

conditions.

Control

Reproduces by seed. Hand-pulling and removing all parts of

the root on small infestations with monitoring for regrowth.

Similar Species

Non-native:

Other agricultural weeds in the Santalaceae

family

Native:

Northern bedstraw

(Galium boreale)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

150

Thistle, Bull

(Cirsium vulgare)

Native to Eurasia, bull thistle is a biennial in the Asteraceae

(Sunflower) family.

Identication

Pink to purple

droplet-shaped flower head

, up to 5 cm

in diameter.

Bracts are narrow with spined tips around

entire base.

Basal rosette produced in first stage of growth,

flowering stem in second. Large rosette, leaves are wrinkled,

coarse hairs on upper side and soft hairs on underside

deeply lobed and up to 30 cm long with 1 cm spine on each

tip.

Stem up to 1.5 m tall

and branched. Short fleshy taproot.

Habitat

Thrives in full sun and can tolerate a wide range of conditions.

Control

Reproduces by seed. Long-term commitment required

for control. Hand-pulling, digging, mowing, grazing and

herbicide.

Similar Species

Non-native:

Canada thistle

(Cirsium arvense)

with smooth

upper leaves and smaller flowers and other thistle species

(

Carduus

and

Cirsium

spp.)

Native:

Native thistle species (

Cirsium

spp.)

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

151

Thistle, Canada

(Cirsium arvense)

Native to northern Europe, Canada thistle is a perennial in the

Asteraceae (Sunflower) family.

Identication

Clusters of purple-pink-white flowers, 1.5-2 cm in diameter

form on branch ends. Bracts have weak prickles (no spines).

Leaves alternate, lobed, lance-shaped, edges wavy, spine-

tipped and stalkless. Stems are prickly, erect, 30-120 cm tall,

branched and slightly hairy. White horizontal and vertical

creeping roots can spread up to 4.5 m horizontally and

6 m deep.

Habitat

Thrives in a variety of soil types and drought resistant.

Control

Reproduces by seed and creeping roots. Mowing, grazing and

herbicide.

Similar Species

Non-native:

Plumeless thistle

(Carduus acanthoides)

, marsh

thistle

(Cirsium palustre)

, purple-flowered knapweeds

(

Centaurea

spp.)

Native:

Native thistle species (

Cirsium

spp.)

Super

Widespread

WEED CONTROL ACT DESIGNATION:

NOXIOUS

152

Thistle, Marsh

(Cirsium palustre)

Native to Europe, marsh thistle is a biennial in the Asteraceae

(Sunflower) family. It has been known to hybridize with

Canada thistle.

Identication

Few to many purple flower heads in dense clusters at branch

tips; bracts spineless. Basal rosette produced in first stage of

growth, flowering stem in second. Lobed leaves are 15-20 cm

long and covered with long, sticky hairs, woody veins on the

underside. Leaves are larger and stemless toward the base.

Reddish stems are slender with spiny wings, lower stems

primarily unbranched, branched at top, thick and covered in

long sticky hairs, up to 1-3 m tall.

Fibrous roots. Up to 2,000

seeds per plant.

Habitat

Prefers moist clay, open, undisturbed

habitat, and can be a problem in cut blocks.

Control

Reproduces by seed. Repeated mechanical control in first

year (rosette stage) or before seed set.

Similar Species

Non-native:

Canada thistle

(Cirsium arvense),

plumeless

thistle

(Carduus acanthoides)

Native:

Native thistle species (

Cirsium

spp.)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

153

Thistle, Nodding

(Carduus nutans)

Native to Europe, nodding thistle (musk thistle) is a biennial

in the Asteraceae (Sunflower) family.

Identication

Large, nodding, purple flower with large thorny bracts;

up to 8 cm in diameter.

Basal rosette produced in first

stage of growth, flowering stem in second. Clasping leaves,

alternately arranged on the stem with deeply lobed, wavy

edges, spines along the edge, hairy, sometimes pinkish and

up to 25 cm long with a prominent midrib. Spiny stem is hairy

and 20-250 cm tall. Fleshy taproot. Each flower head may

produce hundreds of seeds.

Habitat

Intolerant of excessively wet, dry or shady conditions.

Control

Reproduces by seed. Hand-pulling, mowing and herbicide

before seed set.

Similar Species

Non-native:

Plumeless thistle

(Carduus acanthoides)

, marsh

thistle

(Cirsium palustre)

Native:

Native thistle species (

Cirsium

spp.)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

154

Thistle, Plumeless

(Carduus acanthoides)

Native to southern Europe and western Asia, plumeless

thistle (bristly thistle, spiny plumeless thistle) is a biennial or

sometimes winter annual in the Asteraceae (Sunflower) family.

Identication

Purple flower head mostly solitary at stem and branch tip

with spine tipped bracts,

flower head less than 2 cm

. Basal

rosette produced in first stage of growth, flowering stem in

second. Clasping leaves are alternate, hairy and lobed with

spines along edges and at leaf tip. Stem is covered in winged

ridges,

2-5 mm spines along the stem right to flower base

up to 2 m tall. Large, fleshy taproot.

Habitat

Prefers sandy-loam soils with

early season precipitation.

Control

Reproduces by seed. Hand-pulling and herbicide before

seed set.

Similar Species

Non-native:

Marsh thistle

(Cirsium palustre)

, Canada thistle

(C. arvense)

, nodding thistle

(Carduus nutans)

Native:

Native thistle species (

Cirsium

spp.)

Isolated

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

155

Toadax, Dalmatian

(Linaria dalmatica)

Native to Europe, dalmatian toadflax is a short-lived perennial

in the Scrophulariaceae (Figwort/Snapdragon) family. It is

unpalatable or mildly toxic to livestock.

Identication

Snapdragon-like, yellow flowers with darker yellow spot on the

lower lip and long spur extending from the flower base.

Leaves

are waxy, pale-to-bluish green, oval to

heart-shaped

, alternate

with a pointed tip and

clasp the stem

. Stems to 120 cm tall,

robust and waxy. Deep, woody taproot with horizontal roots and

buds that form new stems. Tiny brown-black seeds form in a two

oval capsules; up to 500,000 seeds per plant.

Habitat

Prefers full sun and coarse textured, well-

drained soils that are pH neutral to slightly

alkaline. Primarily found low-mid elevations

that are sheltered and/or have southern

exposures.

Control

Reproduces by seed and creeping roots. Repeated hand-

pulling, biocontrol (the dalmatian toadflax stem-boring weevil,

Mecinus janthiniformis

) or herbicide.

Similar Species

Non-native:

Yellow toadflax

(Linaria vulgaris)

leaf shape

differs

Native:

None

Regionally

common

WEED CONTROL ACT DESIGNATION:

NOXIOUS

156

Toadax, Yellow

(Linaria vulgaris)

Native to Europe, yellow toadflax (common toadflax, butter-

and-eggs) is a perennial in the Scrophulariaceae (Figwort/

Snapdragon) family.

Identication

Snapdragon-like, yellow to pale yellow flowers with orange

spot on lower lip and long spur extending from the flower

base.

Leaves are narrow, pale-to-grey green, linear to

lance-shaped

, alternate and

attach directly to stem but not

clasp

. Stems to 100 cm tall, erect and usually unbranched.

Extensive, creeping root system. Up to 5,000 seeds per

plant stem.

Habitat

Prefers sandy-gravelly soils but is tolerant of a wide range of

growing conditions.

Control

Reproduces by seed and creeping roots. Repeated hand-

pulling or herbicide.

Similar Species

Non-native:

Dalmatian toadflax

(Linaria dalmatica)

leaf

shape differs, may resemble leafy spurge

(Euphorbia esula)

before flowering, but no milky sap

Native:

None

Widespread

WEED CONTROL ACT DESIGNATION:

NOXIOUS

157

Ventenata

(Ventenata dubia)

Native to southern Europe, northern Africa, and western Asia,

Ventenata is a winter annual grass in the Poaceae (Grass) family.

Identication

Spike is pyramid-shaped

, 15-20 cm long with 2-5 branches.

Each spikelet has 2-3 florets, which have a short, straight

awn, while

upper florets have a 90° bend to the twisted

awns

that help drive it into the ground upon maturity. The

plant becomes straw coloured when mature. Stems are long,

thin, and wiry. Leaves are hairless, located primarily on the

lower half of the plant. On seedlings, leaves are narrow and

may appear rolled in.

Habitat

Typically grows in clay and clay-loam

soils that are shallow and rocky.

Control

Reproduces by seed. Herbicide, hand-pulling or mowing

before seed set, planting competitive crops or vegetation.

Similar Species

Non-native:

Downy brome (

Bromus tectorum

) and Japanese

brome (

Bromus japonicus

)

Native:

Annual hairgrass (

Deschampsia danthonioides

) has

smaller, rounder seeds, and ricegrass (

Eriocoma hymenoides

)

has longer spikes

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

158

Waterhemp, Tall

(Amaranthus tuberculatus)

Native to the eastern United States, tall waterhemp is an annual

herbaceous plant in the Amaranth (Pigweed) family. Herbicide

resistance makes it difficult to control.

Identication

Flowers form a long (10-20 cm long), spiky cluster that can vary

in colour from green to red. Only female plants produce seeds.

Stems are smooth and hairless, growing up to 3 m in height.

Leaves are narrow and hairless

, 2-10 cm long and 1-3 cm wide,

with upper leaves reduced. Mature leaves have wavy-like margins,

lack a notched tip, and leaf stalks are shorter than the leaf blade.

Seeds are small, 0.8-1.3 mm long, oval-shaped, and dark reddish

brown in colour.

Habitat

Well-adapted to grow under

variable conditions, including areas prone to

drought and moist to wet conditions.

Control

Reproduces by seed. Herbicide, hand-pulling or mowing before

seed set, planting competitive crops or vegetation, or herbicide.

Similar Species

Non-native:

Redroot pigweed (

Amaranthus retroflexus

), green

pigweed (

Amaranthus powellii

) and Palmer amaranth (

Amaranthus

palmeri

). Tall waterhemp has narrower leaves without a notched

tip, and the leaf stalks are shorter than the leaf blades.

Native:

None

Not known to

be present

WEED CONTROL ACT DESIGNATION:

PROHIBITED NOXIOUS

159

Wild Caraway

(Carum carvi)

Native to Eurasia, wild caraway (caraway, meridian fennel) is

a biennial in the Apiaceae (Carrot) family.

Identication

Several clusters of white to pale pink

umbel shaped flower

heads

on long stalks. Basal rosette produced in first stage

of growth, flowering stem in second. Leaves are alternate,

compound and

finely divided

(similar to carrot leaves); basal

and lower leaves stalked. Stems are usually single, glossy,

branched in the upper plant and grow to 90 cm tall; may be

several stems per plant. Narrow parsnip-like taproot. Fruit is

crescent-shaped with ridges and 2 mm long.

Habitat

Prefers full sun and tolerates a wide

range of soil types, pH and climates, but

intolerant to complete shade.

Control

Reproduces by seed. Herbicide, repeated hand-pulling or

cultivation before seed set.

Similar Species

Non-native:

Queen Anne’s lace

(Daucus carota)

finger-like

bracts and hairy stems, wild parsnip

(Pastinaca sativa)

Native:

Common yarrow

(Achillea millefolium)

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

160

Wild Parsnip

(Pastinaca sativa)

Native to Europe and Asia, wild parsnip is a member of the Apiaceae

(Carrot) family. It is a biennial or short-lived perennial. Wild parsnip is

a root vegetable but has escaped cultivation and spread throughout

much of the temperate world. Toxic to livestock. Contact with plant

not recommended due to potential skin irritation.

Identication

The flowers are yellowish-green and grow in a flat-

topped cluster about 10–20 cm wide. Each cluster has 6–25 stems

that spread out from one point, with small flowers at the ends.

Leaves are alternate, and pinnately compound, and up to 15 cm

long. Leaves become progressively reduced in size and presence

up the stems. Leaf stalks are grooved and clasp the stem.

Stems

grow up to 2 m high

, are grooved, hollow, with sparse hairs.

Habitat

Does best in rich, calcareous,

and alkaline soils and in mesic to dry

soils, but tolerates wet soil. Prefers

partial to full sun.

Control

Reproduces by seed and occasionally

from root fragments left in the soil. Hand-pulling,

herbicide, digging or cultivating prior to seed set.

Similar Species

Non-native:

Giant hogweed

(Heracleum mantegazzianum)

grows

much taller, up to 5.5 m tall. Poison hemlock (

Conium maculatum

Hemlock species (

Cicuta

), these have white flowers.

Native:

Cow parsnip (

Heracleum maximum

) has white flowers.

Similar flowers to Heart-leaved Alexander (

Zizia aptera

) with

different leaves,

Angelica

spp.

Regionally

common

WEED CONTROL ACT DESIGNATION:

UNREGULATED

161

GLOSSARY

Alternate:

Referring to a

leaf or bud arrangement in

which there is one bud or

one leaf at a node.

Annual:

A plant that lives

one year or less. There are

both winter and summer

annuals. A winter annual is

a plant that germinates in

the fall, overwinters, and

regenerates the following

spring from its taproot

to complete its life cycle

before summer begins. A

summer annual is a plant

that germinates in the

spring and completes

its life cycle by the end

of summer in the same

calendar year.

Auricle:

Small ear-like

projection from the base

of a leaf that wraps around

the stem.

Awn:

Hair or bristle-like

appendage in some cereal

and other grasses.

Basal:

Refers to the base of

the plant.

Biennial:

A plant that lives

for two growing seasons,

normally producing a basal

rosette the first year and

the flower and fruit the

second year.

Biocontrol:

A method of

introducing the natural

predators of weeds into

the environment where

they have become invasive

while establishing without

such pressures, to restore

ecological balance.

Bract:

Modified leaf or leaf-

like structure at the base

of the flower, usually below

the petals or flower cluster.

YELLOW TOADFLAX

162

Capsule:

Dry fruit chamber

that holds more than one

seed.

Clasping:

Partly surrounding

the stem.

Fibrous Roots:

Root system

with many, fine, diffuse

roots.

Flower Head:

A cluster of

individual flowers in one

compact unit. Also referred

to as an inflorescence.

Gland:

A plant structure

which secretes one or more

viscous products.

Leaflet:

Each of the leaf-

like structures that together

make up a compound leaf.

Ligule:

The thin

membranous appendage at

the junction of the leaf and

the leafstalk.

Lobed:

Divided less than

one-half the distance to the

base or mid-vein, usually

rounded or obtuse.

Midrib:

The central axis or

vein of the leaf blade or

leaflet.

Node:

Part of a plant stem

from which one or more

leaves emerge, often

forming a slight swelling or

knob.

Nutlet:

Hard, small,

one-seeded fruit, usually

referring to fruits of the

Boraginaceae members.

Used for only a few

descriptions.

Opposite:

Term applied to

leaves or buds occurring in

pairs at a node.

Palmate:

Leaflets, lobes, or

veins which arise from the

same point at the tip of the

stalk, which gives them a

hand-like appearance.

Perennial:

Plants that

live three or more years.

There are both simple

perennials and creeping

rooted perennials. Simple

perennials feature tap roots

and grow as individual

plants. Creeping rooted

perennials feature many

long horizontally oriented

underground rhizomes

radiating out from parent

plants, interconnected

and capable of generating

multiple new plant shoots.

Pinnate:

Leaflets or lobes

developing from several

different points along the

main leaf axis.

Plume:

A hair-like or

featherlike structure, often

on a seed.

163

Rhizome:

A horizontal

stem growing beneath the

ground which can develop

roots or sprouts at the

joints.

Rosette:

A cluster of

leaves radiating out from

the base of the plant.

Sepal:

One of the

outermost flower

structures, usually

enclosing the other flower

parts in the bud.

Sheath:

A protective

covering at the base of

the leaf stem that partly

surrounds the stem.

Spike:

An unbranched

flower head that bears

stemless flowers; stemless

flowers are attached

directly without stalks.

Common for grasses.

Spikelet:

The basic unit of

a grass flower.

Spur:

Any long, narrow

(sometimes tubular)

extension of a petal.

Stamen:

The male

fertilizing organ of a

flower, comprising the

anther and filament.

Stolon:

A horizontal stem

growing above the ground,

which can develop roots or

sprouts at the joints.

Taproot:

The primary

descending root along the

vertical axis of the plant

which is larger than the

branching roots.

Tuber:

Specialized

underground part of a

stem or creeping root from

which new plants arise.

Umbel:

A flower head

comprised of several

individual flowers, in which

the flowers’ stems arise

from a common point,

ascend in all directions,

and form a relatively level

topped flower cluster

(upside down umbrella).

Whorl:

Arrangement of

three or more similar

structures (petals,

stamens, bracts, leaves,

etc.) radiating from a

common point.

164

Black Medic

Medicago lupulina

Birdvetch

Vicia cracca

Bachelor Buons

Centaurea cyanus

Bluebur

Lappula squarrosa

Caragana

Caragana arborescens

Thumbnails of Other Common Weeds

Dandelion

Taraxacum officinale

Flixweed

Descurainia sophia

Goatsbeard

Tragopogon pratensis

Lambsquarters

Chenopodium album

Pineappleweed

Matricaria discoidea

Plantain

Plantago major

Prostrate Knotweed

Polygonum aviculare

165

Thumbnails of Other Common Weeds

Russian Thistle

Salsola tragus

Round Leaved Mallow

Malva pusilla

Quackgrass

Elymus repens

Shepherd’s Purse

Capsella bursa-pastoris

Stinkweed

Thlaspi arvense

PURPLE LOOSESTRIFE

Yellow Sweet Clover

Melilotus officinalis

166

CREDITS

PHOTOS



Alberta Invasive Species Council



Alberta Lake Management

Society



Andreas Manz, inaturalist.org,

licensed under CC0



BC Ministry of Forests, Key to

Identification of Invasive and

Native Hawkweeds in the Pacific

Northwest, 2023



Beth Hoar, Government of

Alberta



Brian Clapp, Union County Weed

Control Dept



Bruce Ackley, The Ohio State

University, Bugwood.org



Charles T. Bryson, USDA

Agricultural Research Service,

Bugwood.org



Chris Evans, University of Illinois,

Bugwood.org



Chris Lee, inaturalist.org, licensed

under CC0



Christopher Neeser, Government

of Alberta



Daniel Laubhann, City of

Edmonton



Donna R. Ellis, University of

Connecticut, Bugwood.org



Edmonton and Area Land Trust



Either Rosemarie De Clerck-

Floate (AAFC/AAC)



Étienne Lacroix-Carignan,

inaturalist.org, licensed under

CC0



Fred Paulson, Interlake Weed

District



Government of Alberta



Illustrated Flora of British

Columbia Volumes 1–8, eds. G.W.

Douglas; Straley, G.B.; Meidinger,

D.V.; Pojar, J. 1998–2002.

Reproduced with permission of

the Province of British Columbia



Irene, inaturalist.org, licensed

under CC0



James H. Miller, USDA Forest

Service, Bugwood.org



Jane Mangold, Montana State

University



Jeff Nesbitt, Pacific County

Noxious Weed Control Board



Jennifer Andreas, Washington

State University



Jesse Rorabaugh, inaturalist.org,

licensed under CC0



John D. Byrd, Mississippi State

University, Bugwood.org



Joseph LaForest, University of

Georgia, Bugwood.org



Joseph M. DiTomaso, University

of California - Davis,

Bugwood.org



Josh Wagoner, Montanta

Government



Julie Sanderson, Chelan County

Noxious Weed Control Board



Kallum McDonald



Kelly Cooley, CoolPro Solutions

Environmental Consulting



King County Noxious Weed

Control Program



Leslie J. Mehrhoff, University of

Connecticut, Bugwood.org



Matthew Martin, King County

Noxious Weed Control Program



Maureen Vadnais, Government

of Alberta



Megan Evans, Alberta Invasive

Species Council



Michael Shephard, USDA Forest

Service, Bugwood.org



Michèle Ammeter, Macdonald

Weed District

167



Nicole Kimmel, Government of

Alberta



Paige Kuczmarski, Alberta

Invasive Species Council



Parks Canada



Phil Westra, Colorado State

University, Bugwood.org



Quillipede, inaturalist.org,

licensed under CC0



Reuven Martin, inaturalist.org,

licensed under CC0



Ross Recker, University of

Wisconsin-Madison, Bugwood.

org



Roy Brunskill, King County

Noxious Weed Program



Sarah Schumacher, Wheatland

County



Shanda Zettle, Tri-County

Cooperative Weed

Management Area



Steve Dewey, Utah State

University, Bugwood.org



Terry English, USDA APHIS

PPQ, Bugwood.org



Todd Green, Newell County



USDA APHIS PPQ - Oxford,

North Carolina , USDA APHIS

PPQ, Bugwood.org



Utah State University,

Bugwood.org



Valerie Sowiak, Government of

Alberta



Wendy VanDyk Evans,

Bugwood.org



Wheatland County

IMAGES (AIASSISTED)



Steven Tannas - images

created using digital editing

and Google Gemini

ILLUSTRATIONS



Andre Lemay, Government of

Alberta



Paige Kuczmarski, Alberta

Invasive Species Council

168

RESOURCES/REFERENCES

For more information contact your local county, Agricultural

Fieldman, municipal Weed Inspector, Bylaw Officer or refer to

the following books and websites below:

Alberta Invasive Species Council (2013). Invasive Plant

Factsheets. Web. Retrieved from:

www.abinvasives.ca

Alberta Lake Management Society (2020). Aquatic Plants of

Alberta 2nd Edition. Web. Retrieved from:

alms.ca/plant-id-

book/

Association of Alberta Agricultural Fieldmen (2021). Web.

Retrieved from:

www.aaaf.ab.ca

Bubar, C., McColl, S., Hall, L. (2000). Weeds of the Prairies.

Agdex 640-4. Alberta Agriculture and Forestry.

CABI Invasive Species Compendium (2021). Web. Retrieved

from:

www.cabi.org/ISC

Centre for Invasive Species & Ecosystem Health (2021).

Retrieved from:

www.bugwood.org

Invasive.org (2018). Web. Retrieved from:

www.invasive.org

Kuczmarski, P., Biggs, M., Hardie, C., and Primeau, D.

(2018). Aquatic Invasive Species Pocket Guide. Alberta

Environment and Parks. Web. Retrieved from:

open.alberta.

ca/dataset/ed4ad469-dc64-4847-9a58-3904818c14d3/

resource/539876aa-9f84-402b-917c-f4eb46ac2dc9/

download/aispocketguide-jul2018.pdf

McClay, A.S., Fry, K.M., Korpela, E.J., Lange, R.M. and Roy, L.D.

(2004). Costs and Threats of Invasive Species to Alberta’s

Natural Resources. Alberta Sustainable Resources Development.

Michalsky, S., Neville, M., and Miller, A.J. 2022. Targeted

Grazing: Plant and Animal Interactions. Montana State

University, Invasive Plant Identification Guide.

Morton, D., Kimmel, N. (2016). Weed Seedling Guide 2nd

Edition. Agdex 640-9. Alberta Agriculture and Forestry.

Royer, F., Dickinson, R. (1999) Weeds of Canada and the

Northern United States. Lone Pine Publishing.

Royer, F., Dickinson, R. (2014) Weeds of North America.

University of Chicago Press.

169

University of Georgia, Center for Invasive Species and

Ecosystem Health (2021). EDDMapS. Web. Retrieved from:

www.eddmaps.org

USDA National Invasive Species Information Centre (2021).

Web. Retrieved from:

www.invasivespeciesinfo.gov

Wheatland County (2013). Alberta Invasive Plant

Identification Guide. Web. Retrieved from:

open.alberta.

ca/dataset/8bb61884-bbfb-4640-bd5d-96f6e633d4ee/

resource/275f7dbe-8116-4d81-ba95-329df950be7e/

download/6740590-2013-alberta-invasive-plant-

identification-guide-2013-06-13.pdf

Wheatland County (2017). Identification Guide for Alberta

Invasive Plants. Web. Retrieved from:

aaaf.ab.ca/uploads/

pdf/Weed_ID_Guide_2017.pdf

Whitson, T.D., Burrill, L.C., Dewey, S.A., Cudney, D.W., Nelson,

B.E., Lee, R.D., Parker, R. (2012). Weeds of the West. Western

Society of Weed Science.

Wilson, L. M. (Revised 2007). Key to Identification of

Invasive and Native Hawkweeds (Hieracium spp.) in the

Pacific Northwest. Ministry of Forests and Range, Forest

Practices Branch, Invasive Alien Plant Program. British

Columbia. Retrieved from: h

ttps://www.for.gov.bc.ca/hfp/

publications/00230/Hawkweed%20key_PNW_R3-June06.pdf

Innotech Alberta Ecosystem Management (2019). Alberta

Weed Compendium. Alberta Agriculture and Forestry.

BLUEWEED

170