Brown Knapweed

Brown Knapweed, Brown-Ray Knapweed

Centaurea jacea L.

Asteraceae (Aster Family)

▲ mature, flowering plant

▲ ▼ flowers and buds

▲ inflorescence bud

Centaurea jacea L., Brown Knapweed: (Bayer Code: CENJA; US Code CEJA)

  • Simple perennial with woody rootstock that grows 1-3 feet tall
  • Has pinkish-purple flowers (head inflorescences) at tips of branches
  • Bracts on the inflorescence are brown to reddish-brown with transparent margins and tips; tips may split into lobes
  • Leaves are lanceolate and entire or with a few teeth, not deeply lobed as in other knapweeds
  • Can distinguish from other knapweeds by the inflorescence bracts, which do not have any or many spines along their edges, as do other knapweeds (spotted knapweed, black knapweed)
  • Can be an aggressive weed, but so far not as invasive as spotted knapweed, diffuse knapweed, russian knapweed, and others
  • The papery-edged, brown bracts distinguish brown knapweed from the dark brown to purple-brown, tiny-tooth-edged bracts of Greater Knapweed (Centaurea scabiosa), Black Knapweed (Centaurea nigra), Spotted Knapweed (Centaurea stoebe) and from the green-tan papery-edged, non-spiny bracts of Russian knapweed (Acroptilon repens)

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(Updated January 19, 2019)