Centaurea stoebe, August 11, 2021
Common & scientific name
Spotted knapweed, Centaurea stoebe
Family
Sunflower, Asteraceae
Location
Roadside, 8,300’
Fun, weird, helpful, or little known fact
Spotted knapweed is native to eastern Europe, and was introduced to North America, “probably as a contaminant in alfalfa (Medicago sativa) seed and/or ship's ballast, in the late 1800s,” according to the US Forest Service. In 1920, the distribution of spotted knapweed in North America was limited to the San Juan Islands, but by 1998 it had spread to 326 counties in the western United States, including every county in Washington, Idaho, Montana, and Wyoming. It is now on the march in Colorado. Ackerman’s Flora of Colorado does not document it in Pitkin County, but here it is.