Invasive Plants

Negative Impact of Weeds

Noxious and restricted weeds are plants introduced from Europe and Asia.

• Unlike native plants, invasive species are not kept in check by insects, fungi or plant pathogens.
• These weeds present a real threat to the biological diversity of the park. They drastically affect native ecosystems by decreasing native biodiversity, impacting plant and animal life, and increasing soil erosion.

Fish Creek Provincial Park has an active weed control program.

• Four methods are used to control invasive species: biological, mechanical, manual and chemical.
• Criteria used to select the method include: weed species, proximity to water, other plant species in the area and wildlife.

Weeds Found in Park

Restricted Weeds in the Park

Nodding thistle  (Carduus nutans) 

• Currently a minor problem in the park
• Pulled when found
• Locations mapped

Noxious Weeds in the Park

Scentless chamomile (Matricaria maritima)

• Found in all areas of the park
• Spreads quickly
• Can be controlled by pulling and bagging plants prior to flowering completion which prevents seed formation and distribution

Toadflax (Linaria vulgaris) 

• Has potential to become a major problem in the park
• Current population level in the park unknown

Purple loosestrife (Lythrum salicaria) 

• Has the ability to totally destroy wetlands areas
• Very little found in the park
• Known occurrences dug up (including all roots possible) and disposed of
• Site mapped and checked the next year
• Not yet found at the same site twice

Canada thistle (Cirsium arvense) 

• Most plentiful weed in the park
• Spreads by seeds, freely sprouting, and creeping root stalks

Leafy spurge (Euphorbia esula) 

• Most problematic weed in the park
• Perennial that spreads by seeds and creeping root stalks
• Milky sap can cause blisters and dermatitis
• Overwhelms other plant species by its early and rapid growth and by releasing a chemical that inhibits their growth
• Mature pods eject seeds up to four metres
• New plants can also develop from buds on the extensive root system

Nuisance Weeds

• Nuisance weeds are the most common weeds, widespread across the province.
• Further spread is almost impossible to stop.  These weeds already occupy every area to which they are biologically suited.
• Nusiance weeds are usually easy to control in crops.
• They are listed primarily so weed managers keep an eye on them.

More Info

• Weed Control Act and Regulations