bull thistle USDA PLANTS SYMBOL: CIVU
Cirsium vulgare (Savi) Ten.
Synonym(s): common thistle, spear thistle

Bull thistle is an annual or biennial, herbaceous plant that invades disturbed areas throughout the United States. The spiny, spreading, winged stems are up to 7 ft. (2.1 m) tall. Leaves are 3-12 in. (7.6-30.5 cm) long, lance-shaped and very hairy. Flowers develop, at the apex of the plant, from June to September. The purple flower heads are 1.5-2 in. (3.8-5.1 cm) in diameter and 1-2 in. (2.5-5.1 cm) long with narrow, spine-tipped bracts. Bull thistle can invade almost any type of disturbed area, such as forest clearcuts, riparian areas and pastures. Plants can form dense thickets, displacing other vegetation. The spiny nature of the plant renders it unpalatable to wildlife and livestock and reduces the forage potential of pastures. Bull thistle is native to Europe, western Asia, and northern Africa. It is thought to have been introduced to the eastern United States during colonial times and the western United States in the late 1800s. It is currently found in all 50 states.

Identification, Biology, Control and Management Resources