bull thistle

Cirsium vulgare (Savi) Ten.

Description from Invasive.org

Appearance
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.
Foliage
Leaves are 3-12 in. (7.6-30.5 cm) long, lance-shaped and very hairy.
Flowers
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.
Fruit
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.

Resources

Selected Images from Invasive.org

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Flower(s) close up
Loke T. Kok, Virginia Polytechnic Institute and State University, Bugwood.org
Additional Resolutions & Image Usage
Competition under dead fir killed by budworm. Swale Creek, Under dead fir killed by western spruce budworm (Choris¬toneura occidentalis); Swale Creek, Heppner Ranger District, Umatilla National Forest, northeastern Oregon
Dave Powell, USDA Forest Service (retired), Bugwood.org
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Foliage Basal rosette
Michael Shephard, USDA Forest Service, Bugwood.org
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Foliage Basal rosette
Michael Shephard, USDA Forest Service, Bugwood.org
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Plant(s) large mature plant on timber harvest area
Dave Powell, USDA Forest Service (retired), Bugwood.org
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Flower(s)
Britt Slattery, US Fish and Wildlife Service, Bugwood.org
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Stem(s)
Dan Tenaglia, Missouriplants.com, Bugwood.org
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Foliage
Dan Tenaglia, Missouriplants.com, Bugwood.org
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Foliage
Steve Dewey, Utah State University, Bugwood.org
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Feature(s) Spines
Steve Dewey, Utah State University, Bugwood.org
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Plant(s) in flower
Steve Dewey, Utah State University, Bugwood.org
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Plant(s) habit
Forest and Kim Starr, Starr Environmental, Bugwood.org
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Flower(s) flower
Forest and Kim Starr, Starr Environmental, Bugwood.org
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Fruit(s) seeds
Forest and Kim Starr, Starr Environmental, Bugwood.org
Additional Resolutions & Image Usage
Plant(s) habit and flowers
Forest and Kim Starr, Starr Environmental, Bugwood.org
Additional Resolutions & Image Usage
Fruit(s)
Forest and Kim Starr, Starr Environmental, Bugwood.org
Additional Resolutions & Image Usage
Flower(s) flowers
Forest and Kim Starr, Starr Environmental, Bugwood.org
Additional Resolutions & Image Usage
Flower(s) habit
Forest and Kim Starr, Starr Environmental, Bugwood.org
Additional Resolutions & Image Usage
Plant(s) Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Vol. 3: 549.
USDA NRCS PLANTS Database , USDA NRCS PLANTS Database, Bugwood.org
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Fruit(s)
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
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Distribution