Scientific Name Synonyms
bull thistle, common thistle, spear thistle
- Cirsium vulgare 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.
- Fruits have several bristles on the tip and are up to 0.2 in. (5 mm) long.
- Ecological Threat
- Cirsium vulgare 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. Cirsium vulgare 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.
- Zouhar, Kris. 2002. Cirsium vulgare. Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory
- Global Invasive Species Database. 2011. Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission
- Oregon Department of Agriculture Plant Programs, Noxious Weed Control
- Washington State Noxious Weed Control Board
- University of California, Jepson Flora Project
- Colorado Weed Management Association
- Flora of North America, www.eFloras.org
- Texas Invasive Plant and Pest Council
- California Invasive Plant Council
- USDA NRCS PLANTS
- USDA ARS GRIN
Images from Bugwood.org