Turkish Thistle, Carduus cinereus¸ was recently discovered in Kalama, and is the first documented location within Washington State. Currently, the nearest documented infestation is in northeastern Oregon. This Class A species on the Washington State Noxious Weed List was added in 2021 for its potential to invade pastures and meadows by crowding out native vegetation and desirable forage species.
Key identification traits of Turkish Thistle from other thistles include spiny-winged main stems and purple narrow compressed flowers on short stems covered in woolly hairs. If you see a thistle in Cowlitz County with winged stems, please contact the Cowlitz County Noxious Weed Control Program for identification.
Turkish Thistle is an annual species growing anywhere from 3 inches tall to 48 inches tall. Winged stems may be unbranched or openly branched, and are loosely covered in soft woolly hairs. The leaves are lobed with spines, basal leaves are about 4 inches in length, while stem leaves are attached directly to the stem and reduce in size towards the upper stem. Non-spherical compressed purple flower heads may occur as one, or in clusters of two to five flowers.
Turkish Thistle may be confused with two other Class A thistle species with winged stems. Italian Thistle (Carduus pycnocephalus) and Slenderflower Thistle (Carduus tenuiflorus) also have winged stems but slightly different characteristics in their flowering patterns. Slenderflower Thistle has been documented in two areas of Cowlitz County, while Italian Thistle has not yet been documented in Cowlitz County.
The Cowlitz County Noxious Weed Control Program has been working very closely with responsible landowners to survey and remove the plants prior to the development of the seed. If you suspect you have this thistle, please contact the Cowlitz County Noxious Weed Control Program for identity confirmation. Knowledge of all existing locations is crucial in efforts to stop this weed from infesting more lands in Cowlitz County. If you have this thistle and can’t control it, please tell us, and we will find a way to help you. We don’t want this plant to spread!
Class A noxious weeds, as defined in WAC 16-750, are those noxious weeds not native to the state that are of limited distribution or are unrecorded in the state and pose a serious threat to the state. As a Class A noxious weed, the state noxious weed law RCW 17.10 establishes that all Class A noxious weeds are to be eradicated.
For more information please contact the Cowlitz County Noxious Weed Control Program by phone at (360) 577-3117; email at noxiousweeds@co.cowlitz.wa.us; or mail at 207 Fourth Avenue North, Kelso, WA 98626. If you live outside of Cowlitz County, and suspect you have this thistle, first contact your county's noxious weed control board for assistance.