Diffuse knapweed

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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.


  • 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