Alturas Field Office

Noxious Weeds


Squarrose Knapweed    (Centaurea squarrosa)
Sunflower Family (Asteraceae)


Squarrose Knapweed
Photo courtesy of the California Department of Food and Agriculture


Next Plant
Next Plant Arrow


Description:  Long-lived, taprooted perennial 12 to 18 inches tall or more. Stems highly branched. Lower leaves deeply divided; upper leaves grayish, and reduced. Flower heads numerous, small, with rose or pink flowers. Phyllaries recurved or spreading with terminal spine longer that lateral spines. Seed heads readily break off when seeds are mature.

Habitat:  Native to Asia. Aggressively grows in dry disturbed areas, particularly in sand or cinders such as roadsides or cinderpits. Invades and replaced native vegetation on rangelands.

Distribution: Squarrose kanpweed in Big Valley (Lassen County and Modoc County) and north or Yreka (Siskiyou County) have infestations of over 100 acres each. Also found scattered along roadways and in adjacent properties in southern Modoc, northern Lassen, and eastern Shasta counties.

Flowering Period: June to August.