Alturas Field Office

Noxious Weeds

 

Yellowspine Thistle   (Cirsium ochrocentrum)
Sunflower Family (Asteraceae)

Yellowspine Thistle
California Department of Food and Agriculture

 
 

Next Plant
Next Plant Arrow

Description:  Biennial or perennial with tubrous creeping roots. Stems to 2-1/2 feet, simple or branched, with dense, short, white wooly hairs. Plant somewhat bushy. Leaves narrowly divided, green to gray, 3 to 8 inches long with tufts of soft wooly hairs on upper surface, densely wooly pubescent on lower surface. Leaf margins irregularly toothed with yellowish spines 1/8 to 1/4 inch long. Flowers solitary or few clustered, terminal, rose to cream colored. Phyllaries covered with cobweb-like hairs, with dark glandular ridge and spreading yellow spine-tip. Seeds light brown, smooth, with tuft of hairs at tip.

Habitat:  Native to the central United States. Invades disturbed areas, rangelands, and pastures.

Distribution:  There are only two known sites of yellowspine thistle in northern California. One is found east of Alturas, and the other along Fandango Pass Road (Modoc County).

Flowering Period:  June to October.