Invasive Plants in Alberta: Acreages

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What is the problem? | Species to watch out for | What you can do | General principles and resources

Land owners and occupiers are responsible for controlling noxious weeds and destroying prohibited noxious weeds under the Alberta Weed Control Act. Listed plants in the Act cause problems for the environment, health or economy. Know your responsibilities under the Act. Regardless of where plants are located, prevention is always the most effective approach in dealing with invasive plants.

What is the Problem?

Acreages are the interface between urban and rural living. They offer the opportunity to enjoy gardening, hobby farming and closer contact with nature while being within reach of the amenities of urban life.
Acreage owners often do not have an agricultural background and may sometimes be less familiar with invasive plants than those who grew up in rural areas.

Ornamental plants can escape from gardens and become invasive, spreading into natural areas or agricultural land.

Acreage owners may not use commercial class pesticides available to farmers and commercial pesticide applicators without proper certification, except for those authorized in provincial legislation.

Currently, herbicides available to acreage owners have the following active ingredients:
  • acetic acid
  • glyphosate
  • 2,4-D alone or in combination with dicamba or mecoprop or both
Acreage owners can purchase these products in domestic as well as commercial class products and sizes. For further information, please refer to the Alberta Government Environmental Code of Practice for Pesticides.

Species to Watch Out For

Many agricultural and pasture weeds can occur on acreages:
  • leafy spurge (Euphorbia esula)
  • yellow toadflax (Linaria vulgaris)
  • scentless chamomile (Tripleurospermum inodorum)
  • Canada thistle (Cirsium arvense)
  • perennial sow-thistle (Sonchus arvensis)
  • common tansy (Tanacetum vulgare)
  • field scabious (Knautia arvensis)
  • burdock (Arctium species)

Leafy spurge (Euphorbia esula)

Some plants grown as ornamentals can also escape and become invasive. Watch out for the following:
  • ox-eye daisy (Leucanthemum vulgare)
  • purple loosestrife (Lythrum salicaria)
  • creeping bellflower (Campanula rapunculoides)
  • yellow clematis (Clematis tangutica)
  • dame’s rocket (Hesperis matronalis)
  • Himalayan balsam (Impatiens glandulifera)
What You Can Do
  • Be alert for new or unfamiliar plants growing on your property and get them identified.
  • Overgrazing can allow weeds to take over in pastures, so limit the number of animals on pastures. Use weed-free hay, if available, when feeding horses and cattle.

Field scabious (Knautia arvensis)

Yellow clematis (Clematis tangutica)

Burdock (Arctium species) great, common, woolly
  • Avoid planting invasive species. Non-invasive alternatives are available for many problem ornamentals, such as blazing star (Liatris) instead of purple loosestrife. Check out “Weed Wise Gardening” from the Alberta Invasive Species Council.
  • Do not plant “wild flower” seed mixes: many of these mixes contain invasive plants. Many Alberta growers can provide native trees, shrubs, grasses and wild flowers.
  • Hand pull or dig out small patches of invasive plants before they go to seed or start to spread.
  • Some weeds with deep root systems like Canada thistle and perennial sow-thistle can be set back by repeated mowing.
  • Re-vegetate disturbed ground with grasses, shrubs or trees to provide strong competition for weeds.

Creeping bellflower (Campanula rapunculoides)

Purple loosestrife (Lythrum salicaria)

Ox-eye daisy (Leucanthemum vulgare)

Dame’s rocket (Hesperis matronalis)

Himalayan balsam (Impatiens glandulifera)

Yellow toadflax (Linaria vulgaris)

Scentless chamomile (Tripleurospermum inodorum)

Canada thistle (Cirsium arvense)

Perennial sow-thistle (Sonchus arvensis)

Common tansy (Tanacetum vulgare)

General Principles and Resources
  • Land owners and occupiers are responsible for controlling noxious weeds and destroying prohibited noxious weeds. Know your responsibilities under the Alberta Weed Control Act.
  • Learn to identify invasive plants.
  • Be alert for invasive plants and respond early when they are found.
  • Reduce the introduction of invasive plants as well as the reproduction and movement of their seeds and plant parts.
  • Reduce soil disturbance, which makes openings where invasive plants can establish.
  • Use effective, appropriate methods to control invasive plants. Alberta Agriculture and Rural Development, Environment and Sustainable Resource Development, municipal Agricultural Fieldmen and Alberta Ag-Info Centre, call 310-FARM (3276), can provide advice on control methods. Always follow label instructions when applying any herbicide.
  • Alberta Invasive Plant Identification Guide (from Wheatland County)
  • Alberta Invasive Species Council factsheets
  • Alberta Weed Control Act and Regulations
  • Alberta Weed Monitoring Network

Learn More

Find out more on this topic and access these additional resources at the following web page: Source: Agdex 640-14. February 2014.
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For more information about the content of this document, contact Chris Neeser.
This document is maintained by Jennifer Rutter.
This information published to the web on February 28, 2014.
Last Reviewed/Revised on August 21, 2018.