Bull Thistle

Cirsium vulgare

 

 

Description: This plant is a biennial forb. In the juvenile phase an individual can form a single rosette with a taproot up to 28 inches long. The rosettes can grow up to 3.3 feet in diameter.  The leaves of bull thistle are lance-shaped and anywhere from 3-12 inches long.  These leaves have prickly hairs on top and are very hairy on the underside.  Flowers are usually solitary and clustered near the ends of shoots and branches, measuring 1-2 inches long.  The fruits of bull thistle are achenes. 

 

Ecological Threat: This plant has no nutritional value for livestock and competes with desirable forage. The sharp spines of this thistle deter livestock and wildlife alike, truly making it a pest. 

 

Biology & Spread: Disturbed areas creative open habitats for seed production and seedling establishment of this invasive species. 

 

Threat in Oklahoma: This invasive species is not suitable for consumption by livestock or wildlife and inhibits the growth of native flora. 

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Management:Integrated Management of Invasive Thistles in Oklahoma