A new species of thistle has been found in the Hells Canyon Wilderness of northeastern Oregon and western Idaho. The Oregon population is found in Wallowa County, which borders Columbia, Garfield, and Asotin Counties in Washington.
Turkish or Spanish thistle (Carduus cinereus) has never been found in North America so this will be a new one to watch out for. See photos below. It was originally identified as Italian thistle (C. pycnocephalus). The plants were generally quite short at the Oregon sites but could grow up to 2 feet. There doesn’t seem to be a lot known about this species but it is worth keeping on your radar.
A paper about this species should be coming out soon (Gaskin et al. Carduus cinereus (Asteraceae) – New to North America, in press).