There are a number of invasive plant species in the Central Kootenay.
Download our most recent priority list here (PDF - 44KB)
For more detailed information on the biology, distribution, and management strategy for each species in our region, please see the Invasive Plant Profiles
Spotted knapweed
Spotted knapweed (Centaurea maculosa) is the most prevalent non-native invasive plant species in the Central Kootenay. Covering thousands of hectares of land in BC, this species is highly competitive and degrades natural plant communities. An individual plant can produce up to 140,000 seeds per square meter, giving little opportunity for native plants to grow.
The invasion of spotted knapweed impacts wildlife, including ungulate winter range habitat. This species forms monocultures that displace native plants and reduce biodiversity, including habitat for the western skink and other threatened animals. As well, spotted knapweed reduces the grazing capacity of land, impacting ranchers and the agricultural community.
Spotted knapweed can be identified by its light pink solitary flowers with stiff black-tipped bracts below it giving a "spotted" appearance. The plant grows from a basal rosette in the first year to almost 2 m tall in the second. The leaves are deeply lobed and the plant is based on a stout taproot.
Once established, spotted knapweed is very difficult to get rid of. Prevention is the best control, maintaining areas that are not infested as "knapweed-free". Mow or otherwise control plants anywhere they can be easily spread, such as along a driveway or roadsides. Be careful not to spread seeds on the undercarriage of your vehicle or on your shoes and gear. For herbicide options, see website below.
Active irrigation on sites is a fairly effective method of control. By watering constantly and regularly, knapweed can be choked out and grasses will emerge. Follow up with pulling knapweed is relatively easy with moist soil.
Since pulling knapweed can be difficult, a local resident has developed a tool that assists. Jimmy Mead has used the "leaf spring" from an old vehicle, attached to a long pole/handle, to form a device for pulling knapweed. Contact the CKIPC for more information.
Biological control has been used for spotted knapweed in the Kootenays for many decades. Biological control involves the release of predators (usually insects) that attack knapweed to weaken the plants. These insects are carefully screened by Agriculture Canada to ensure that they only attack knapweed and no other plant species. Current biocontrol agents for knapweed include seedhead-attacking weevils and flies, and root-attacking weevils and moths. For more information on biocontrol, see this biocontrol web page from the BC Ministry of Agriculture and Lands. The CKIPC can provide insects to residents of the Central Kootenay. Please contact us for more information.
Additional Information:
www.weedsbc.ca/weed_desc/spotted.ht ...
Invasive Plant Profile:
Spotted knapweed - Centaurea biebersteinii - 925.5 KB
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