Description:
Description and Variation: Brown knapweed is a perennial plant with a woody root crown that grows 20 to 48 inches tall, branching near the top. The branches have egg-shaped or lance-shaped undivided leaves that become progressively smaller up the stem. The stem is ridged and sometimes purple-striped. The 3/4-to-one inch, light to dark brown heads are found at the ends of the branches. The somewhat hairy bracts are wider at the tips with broad, thin, papery margins. The center of the bracts is dark brown. The bract tips overlap the base of nearby bracts. The flowers, which bloom from July to October, are rose to purple but rarely white.

• Mechanical: Not known.
• Biological: Urophora quadrifasciata, a seed head gall fly, has been used at a few limited brown knapweed sites in Washington.
• Herbicide: Glyphosate, picloram, 2,4-D, and clopyralid have all been used on knapweeds. Please refer to most recent Pacific Northwest Weed Control Handbook for more information. Read and follow current herbicide labels and recommendations for control. Refer to the State Noxious Weed Control Board site

For More Information:
Detailed information about Brown Knapweed is available at the Washington State Noxious Weed Control Board Web Site.