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Musk thistle identification and control: Carduus nutans

Musk thistle identification and control

Carduus nutans

musk thistle flowers
This Class B noxious weed occurs in abundance in some parts of Washington State and is rare in others. Musk thistle invades pastures, meadows, and fields, displacing native and/or beneficial forage species. As a Class B noxious weed, its control 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.  For more information about noxious weed regulations and definitions, see Noxious weed lists and laws.

For more information about musk thistle, please visit the website of the Washington State Noxious Weed Control Board (external link).

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

Please notify us if you see musk thistle 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. We map all known locations of regulated noxious weeds such as musk thistle in order to help us and others locate new infestations in time to control them.

Musk thistle photos

musk thistle plant
musk thistle stem


Report Musk Thistle in King County, Washington

Locate Musk Thistle in King County, Washington

Related Information


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).