Centaurea diffusa diffuse knapweed

Asteraceae (Sunflower) Family

Washington State-designated as a noxious weed (control required by law)

Non-native Introduced from Central Asia in mid-1800s; now grows throughout Western and Midwestern U.S. & Canada.

Description:

• Upper leaves-narrow
• Lower leaves-divided
• Form a basal rosette
• Grows upright from a taproot
• Annual or short-lived perennial
• Stems branch profusely
• Flowers: white, rose, or purple
• The bracts are covered with comb-like spines

Habitat: widespread & aggressively invasive in non-shaded, well-drained soils in pastures, travel corridors, & bare ground