Ornamental invasive plants

Weed graphicIn 2010, several ornamental invasive plants were added to the noxious and prohibited noxious weed lists under the Alberta Weed Control Act.

Many of these species may be found in your flower beds or garden. These flowers were listed as invasive plants due to their abilities to spread rapidly, often escaping garden boundaries. They can outgrow native species resulting in an impact on natural environments.

Weed Wise Brochure
This brochure by the Alberta Invasive Plant Council lists invasive plants and substitutions. They recommend avoiding all plants with known invasive behaviours (like Gout weed) and provide alternatives even if they are not listed in the Weed Control Act.  Keep this brochure handy when shopping for plants.

Common ornamental noxious weeds:

  • Dame's Rocket (Hesperis matronalis)
  • Creeping Bellflower (Campanula rapunculoides)
  • Yellow Clematis (Clematis tangutica)
  • Common Baby's Breath (Gypsophila paniculata) 
  • Oxeye Daisy (Leucanthemum vulgare)
Common ornamental prohibited noxious weeds:
  • Himalayan Balsam (Impatiens glandulifera)
  • Salt Cedar (Tamarix spp.)
  • St. John's Wort (Hypericum perforatum)
  • Purple Loosestrife (Lythrum salicaria)

Good Gardening Solutions
The easiest solution is to avoid planting any invasive plants and knowing the characteristics and spreading behaviours of the plants you wish to grow.  Often garden catalogues or plant tags will identify a plant as being 'vigorous' or that the plant 'self sows easily'.  Avoid these plants because they have the tendency to spread fast and require a lot of weeding to keep contained.

Remove noxious plants as soon as possible, even if they don't look like they are spreading in your garden.  Some plants, such as Himalayan Balsam, expel seeds up to a distance of 5 meters away when the seed pod is touched.  Other plants like Purple Loosestrife produce hundreds of thousands of seeds that are carried away by water or animals to start an infestation elsewhere.

Avoid Wildflower Mixes
Wildflower mixes often contain invasive plant species that spread rapidly and are not from the local area.  Make sure to check the label for the scientific (Latin) names to know exactly what you are planting in your garden and flower beds.  Avoid purchasing seed mixes that do not include scientific names on the label. If you would like to plant wildflowers, it is best to research native wildflower species common to your area, and plant individual flowers or purchase seed mixes from local reputable growers. For a list of native plant businesses, visit Alberta Native Plant Council for listing information or visit the Canadian Wildlife Federation Wild About Gardening website for more information about native Canadian plants.

Further information or to report a weed concern:
780-417-7100

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Last updated: Friday, May 10, 2013
Page ID: 7722

County Hall: 2001 Sherwood Drive, Sherwood Park, Alberta, Canada T8A 3W7