Step 1. Correctly identify your plant.
Biennial or short-lived perennial with branched stems, up to 3 feet tall.
Rosette leaves deeply lobed, stem leaves alternate and covered with short grayish hairs.
White or pink disk flowers the lower bracts (modified leaves under the flowers) have a comb-like fringed with black tips.
Photo Credit: https://www.tcweed.org/ and Laurel Baldwin, Whatcom County Noxious Weed Control Board
Step 2. Choose your method.
Hand pull or dig removing at least 2-4” of root. It is preferable to pull during the rosette (middle photo) stage, but mature plants can be pulled. Seed any large patches of bare ground with native seed to prevent future weeds.
Spotted Knapweed is allelopathic (chemical inhibition of one plant by another, due to the release of substances acting as germination or growth inhibitors) and reduces biodiversity by choking out native vegetation. It is best to catch and treat early.
Step 3. Repeat.
A single plant can produce up to 25,000 seeds per plant and seeds remain viable for more than 8 years, it is very important to monitor and treat.
To learn more about the biology of Spotted knapweed visit the web page below.