General Information
Species Name: Cirsium vulgare
Also Known As: common thistle, spear thistle
Family: Asteraceae (Aster)
Growth Form: Forb
Life Span: Biennial
Flowering Dates: July-September
Origin: Europe, Asia, Northern Africa
Toxic: No
Noxious: Yes. Bull thistle is listed as a County Designated Noxious Weed for Brown and Rock County. Please report to the local weed control authority if found in the following counties: Brown and/or Rock.
Watchlist: No
Why Is It Invasive?
Bull thistle may outcompete native plants and desirable wildlife and livestock forage plants. It can invade most any disturbed habitat and grow in dense thickets. Hay price may decline with the presence of bull thistle.
What Does It Look Like?
General Characteristics
Bull thistle is a biennial herbaceous plant growing between 3 to 7 feet tall with one upright branched stem. Bull thistle is a biennial herbaceous plant. In its first year, it grows as a small round clump of leaves close to the ground (a rosette). Plants overwinter in the rosette stage, then the next spring the plants send up a flowering stalk, set seed, and then die. In its second year, bull thistle can grow up to three to six feet high with a single erect stem with multiple branches. Each plant has a fleshy taproot.
Flowers
Disk-shaped flower heads can be two inches wide and contain hundreds of tiny individual purple flowers. There are long, thin green bracts below the purple flowers. Flowers bloom from July through September.
Leaves
Leaves are alternate (come off the stem one at time at each leaf node). Leaves are coarsely lobed with each lobe having a spine at its tip. Leaves are hairy and the upper leaf surface is rough.
Stems
Numerous straw-colored seeds with white, feathery tufts are dispersed by wind. They remain viable in the soil for over 10 years.
Seeds
Seeds are less than 0.16 inches (4 mm) long.
Photos
Credit: Ansel Oommen, Bugwood.org
Credit: Juan Campá, MGAP, Bugwood.org
Where Does It Grow?
Bull thistle prefers to grow in disturbed areas like pastures, meadows, old fields, gardens, roadsides and ditches.
How Does It Spread?
Bull thistle was introduced to the United States in the early 1800s. Bull thistle was likely accidentally introduced from seeds in ship ballast or as a seed contaminant with other seeds that were brought over purposefully. Today, bull thistle is found in every state.
How Do I Control It?
Mechanical
Contact your county weed control authority to determine appropriate removal methods.
Cultural
When buying hay or forage, check to make sure it is weed-free certified. Management should include proper grazing and rotational grazing techniques that would maintain rangelands and prevent invasion. Disturbed areas should be re-seeded with desirable species to prevent spread.
One way that invasive plant seeds and fragments can spread is in soil. Sometimes plants are planted purposefully. You can prevent the spread of invasive plants.
PlayCleanGo: Stop Invasive Species in Your Tracks
REMOVE plants, animals and mud from boots, gear, pets and vehicles.
CLEAN your gear before entering and leaving the recreation site.
STAY on designated roads and trails.
PLANT non-invasive species.
Chemical
Please refer to the 2025 Guide for Weed, Disease and Insect Management in Nebraska or contact your county weed control authority.
What Should I Do If I See It in Nebraska?
If you see purple loosestrife in Nebraska, you should report it to your county weed control authority. For guidance on what information to include in your report, check out our reporting tips.
References and More Information
California Invasive Plant Council
Center for Invasive Species and Ecosystem Health
Minnesota Department of Natural Resources
National Invasive Species Information Center
Nebraska County Designated Noxious Weeds
Nebraska Department of Agriculture
Nebraska Weed Control Association
North Carolina Extension Gardener Plant Toolbox
Stubbendieck, J., Coffin, M., & Dunn, C. (2019). Weeds of the Great Plains. Nebraska Department of Agriculture.