Spotted Knapweed

(Centaurea maculosa)

Spotted Knapweed is of European origin. It is a biennial, or short-lived perennial forb with a stout taproot. It can have one or more stems that are branched , and from 1 to 3 feet tall. Basal leaves are up to 6 inches long, and narrowly elliptic in shape, but can vary. Flowering heads are solitary on top stem branches. Bracts around the heads are stiff and tipped with a dark, comb-like fringe. This is a key difference between spotted and diffuse knapweeds; the bracts of diffuse are tipped with a definite slender spine. The showy flowers of spotted knapweed are pinkish-purple, or rarely cream colored. Spotted knapweed is often found on rangelands and other drier sites.

 

Managing Spotted Knapweed

Additional Information

CSU Fact Sheet # 3.110 - Diffuse & Spotted Knapweed

 

Kelly Uhing, Colorado Department of Agriculture