Buffalobur (Solanum rostratum Dunal),is a member of the nightshade genus in the potato family. It is native to North America―ranging from central Mexico upward across the Great Plains of the United States―and can now be found throughout the United States. It is a fibrous tap-rooted annual that reproduces solely from seed. It grows 1–2 feet tall and has erect, hairy stems and ascending branches. The stems, leaves and seed pods of buffalobur are covered with long, yellow spines, 1/8–1/2 inch long. Prominently veined, deeply lobed leaves resembling those of a watermelon plant are 2–5 inches long and densely covered with stiff, sharp hairs. The flower of buffalobur is a 5-lobed corolla that is bright yellow and blooms from May to October, depending on location. The fruit of the plant are berries that are enclosed by a spiny calyx that enlarges to form a bur. Each berry produces 50–120 flattened, roundish seeds that are brown to reddish-brown and wrinkled or finely pitted. When mature, the main stem breaks off and the plant tumbles in the wind, scattering seeds―up to 8500 per plant. Drought resistant, buffalobur grows in many soil types, particularly those that are sandy. It occurs in disturbed, dry areas, and is often found along roadsides and in rangeland, overgrazed pastures, fields, and waste areas. It can also be found under bird feeders, as the seed is sometimes a contaminant of bird feed mixes

Photo by: Steve Hurst @ USDA-NRCS Plants Database     ©2001 Larry Blakely

Buffalobur contains the alkaloid solanine that can poison livestock―cattle are particularly susceptible―although most livestock generally avoid eating the plant because of its spiny nature.  Buffalobur should be controlled in pasture settings so that it does not find its way into hay. The plant is also a nuisance because its burs can become tangled in the wool of sheep, resulting in loss of value.

Since this plant is an annual, any control method used to prevent seed production is effective.

Photo by: Joseph M. Di Tomaso UC-Davis, Bugwood.org		Photo by: Whitney Cranshaw Colorado State University Bugwood.org		Photo by: Richard Old XID Services, Bugwood.org

Control

Cultural/Physical: Preventing seed production of this annual plant is fundamental to its eradication, so control efforts should be undertaken before blossoms appear. Because it is not a highly competitive plant, buffalobur can be suppressed by maintaining a competitive vegetative cover.  The spines of buffalobur can cause puncture wounds, so protective clothing and gloves should be worn before attempting physical removal. The plant can be hand-pulled, hoed or dug (moistened soil makes it easier). Repeated mowing and cultivation before flowering are also effective options.

Chemical: The herbicides dicamba, picloram, triclopyr and 2,4-D can be effective in controlling Buffalo bur and should be applied prior to flowering. Spot treatment using glyphosate will also control buffalobur.

More information can be found in the
PNW Weed Management Handbook

Refer to the label for all herbicides
Always follow label directions prior to use

Biological: Natural enemies may be found in native areas, but otherwise no biological control agents are available.

Questions: contact Steve Van Vleet or phone (509) 397 - 6290

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