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purple starthistle flowerThis Class A noxious weed has a limited distribution in Washington State; control and eventual eradication is required in King County. This species is also on the Washington quarantine list (known as the prohibited plants list) and it is prohibited to transport, buy, sell, offer for sale, or to distribute plants or plant parts, seeds in packets, blends or "wildflower mixes" of this species, into or within the state of Washington. Purple starthistle invades pastures, meadows, and fields, displacing native and/or beneficial forage species.

For more information on noxious weed regulations and definitions, see Noxious weed lists and laws.

Additional information on purple starthistle

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

Please notify us if you see purple starthistle 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 purple starthistle is not established in King 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 purple starthistle in order to help us and others locate new infestations in time to control them.

Purple starthistle photos - click thumbnail for larger image

purple starthistle plant
purple starthistle rosette

Report purple starthistle in King County, Washington

Locate purple starthistle in King County, Washington

Related information

Related agencies


Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact staff, see the Noxious Weed Control Program Directory, send an email, or call 206-477-WEED (206-477-9333).