Skip to main content

Dyer's woad identification and control: Isatis tinctoria

Dyer's woad identification and control

Isatis tinctoria

dyer's woad flowers
Dyer's woad was discovered in 1986 in Washington State, growing along railroad tracks in Kittitas County. In 1992, dyer's woad was eradicated from this site. The site is monitored continually, with no new plants found. Removing this plant from the State is a true success story in the fight against invasive species; this is one of the very few noxious weeds that have been eradicated from the State.

Dyer's woad is native to Russia, and was introduced as a crop in 18th-Century England for the extraction of a blue dye from its leaves. Dyers woad was introduced to Utah from Ireland in 1910, as a contaminant in alfalfa seed. The state of Utah has lost millions of dollars in crop damage and loss of wildlife habitat. Tens of thousands of acres in Utah, Idaho and Wyoming are infested with this perennial mustard.

Legal status in King County, Washington

Dyer's woad is listed as aClass A noxious weed because of its impacts and widespread distribution in many western States, including Utah, Idaho, Wyoming, Montana, California and Oregon. It is sometimes found in gardens, and as a Class A noxious weed in Washington State, eradication is required. Dyer's woad is on the Washington Statequarantine list, and it is illegal to buy, sell, transport or offer this plant for sale in the state.

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

Additional information on dyer's woad

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

Please notify us if you see dyer's woad 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 dyer's woad in order to help us and others locate new infestations in time to control them.

Report dyer's woad in King County, Washington

Locate dyer's woad 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).