Spotted and Diffuse Knapweed

Identification

Spotted knapweed (Centaurea biebersteinii ) - Flowers pink to purple, rarely white, disc florets. Bracts have 5-7 pairs of comb like teeth, no spine at bract tip. Leaves alternate on stem ½ to 2 inches long.

Diffuse knapweed (Centaurea diffusa) - Flowers white to rose or purple. Bracts have comb like teeth with a distinct terminal spine. Leaves similar to spotted knapweed.

Spotted Knapweed

Situation in Kansas

Spotted knapweed is known to exist in Nemaha County in a localized area.  Diffuse knapweed is not known to exist in the state, but is present in several Colorado counties near the Kansas border.