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To offer a suggestion or report an error on the King County Noxious Weeds Web site, please contact Sasha Shaw, education specialist.
King County, Washington noxious weed identification and control

Black knapweed
Centaurea nigra

black knapweed plant

Legal Status in King County, Washington

This Class B noxious weed is a Class B Noxious Weed. It has a limited distribution in Washington and control is required in King County.

Additional information on black knapweed

What to do if you find this plant in King County, Washington

Please notify us if you see black knapweed growing in King County. Our program staff can provide the property owner or appropriate public agency with site-specific advice on how best to remove it. Also, because black knapweed is still found in only a few places in the county, we have an opportunity to stop it from spreading if we act quickly. We map all known locations of regulated noxious weeds such as black knapweed in order to help us and others locate new infestations in time to control them.

Black knapweed photos - click thumbnail for larger image

black knapweed flower - please click for larger image black knapweed plant - please click for larger image

Report black knapweed in King County, Washington

Locate black knapweed in King County, Washington

Related information

Related agencies

Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact a staff member at the King County Noxious Weed Control Program, please call 206-296-0290 or by reach them by email.