Bull Thistle (Cirsium vulgare)
Sunflower Family (Asteraceae)
California Department of Food and Agriculture Botany Lab
Description: This biennial stands 1 to 6 feet (3 to 20 decimeters) tall. It generally has one stem that is openly branched above the middle and is often glanular and hairy. Leaves are harshly bristly above, sometimes with densely interwoven hairs. Lower leaves are 4 to 16 inches (10 to 40 cm) long and upper leaves become smaller with spiny wings. Main leaf lobes generally rigidly spreading, spine-margined, with main spines < .5 inches (1.5 cm) long. Blooms are one to several flowers and clustered with bract-like uppermost leaves beneath. Flower heads are 1 to 2 inches (2 to 4 cm) in diameter, hemispheric or bell-shaped, and petals are purple.
Habitat: Native to Eurasia, bull thistle thrives in disturbed areas below 7545 feet (2300meters).
Distribution: Throughout California where ground-disturbing activities have taken place, such as road construction, mining, overgrazing, fire, or logging. Within public lands administered by the Arcata Field Office, bull thistle occurs in the King Range in small numbers on small pockets of land favored by livestock for grazing.
Flowering Period: July through September