Solanum rostratum


Family: Solanaceae

Other common names: Kansas thistle, Texas thistle

Weed Class: C

Year Listed: 1988

Native to: Midwest region of the United States and Mexico

Toxic: livestock

Other Legal Listings: WA Quarantine list, WAC 16-750

additional photos



Why is it a noxious weed?

Buffalobur is generally considered a nuisance in its native range and is toxic to livestock. It is very aggressive in pastures and rangeland, competing with forage plants. Burs can get caught on sheep wool devaluing the wool.

How would I identify it?

General Description: This annual plant is spiny, hairy and around 1/2 to 3 feet tall. The entire plant, except the petals, is covered by straight yellow spines that are 1/8 to 1/2 inch long.

Flower Description: Flowers in clusters (racemes) of 3 to 15. Flowers are yellow, 5-lobed, flat and circular (rotate) and around 1 inch in diameter.

Leaf Description: The leaves are alternate, 2 to 6 inches long, irregularly cut into 5 to 7 lobes, and extremely prickly.

Stem Description: Upper stems are branching, upright, bushy, 1/2 to 3 feet long, and extremely prickly.

Fruit/Seed Description: Fruit is a berry.

May be confused with:

How does it reproduce?

Buffalobur reproduces by seed.

Where does it grow?

Buffalobur is found in fields, overgrazed pastures, yards, roadsides, waste areas, barn yards, and will grow in sandy soils, as well as dry hard soils to rich moist soils of cultivated fields. Please click here to see a county level distribution map of buffalobur in Washington.

How do I control it?

Mechanical Control

Prevention of seed production is possible with repeated, close mowing or hoeing out plants before flower blossoms appear.

Cultural Control


Biological Control


Herbicide Control

Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.


For more information

See our Written Findings for more information about buffalobur (Solanum rostratum).

Additional Photos



Buffalobur flower


Buffalobur growth


Buffalobur leaves


Buffalobur flowers


Spines on stems


flowering plant


leaf detail




pulled plant with many spiny fruits


two pulled plants upside down, showing roots


plants growing on disturbed ground


blooming plant


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