WSU Extension


Weeds : Buffalobur : Solanum rostratum
(revision date: 4/7/2021)

Family: Solanaceae
Cycle: Annual
Plant Type: Broadleaf

Use Integrated Pest Management (IPM) for successful weed management.

Buffalobur is an exceptionally spiny annual plant growing about two feet high. The alternate leaves have deep, rounded lobes and are two to five inches long. The leaves are prickly underneath on the petiole, midrib, and veins. The main stem of the plant is robust, with numerous yellow spines. Yellow flowers about an inch wide are borne throughout the summer. The flowers are roughly star-shaped, with five lobes. The fruit is a 1/2-inch berry that is completely enclosed in the spiny flower base or calyx. Each spiny seed capsule contains many small seeds. Buffalobur is very drought-resistant. SPECIAL INFORMATION: All parts of the plant are toxic. In WASHINGTON, buffalobur is designated as a Class 'C' noxious weed. In OREGON, it is designated as a Class 'B' noxious weed. Intensive control may be required in your county. In addition, buffalobur is on the noxious weed quarantine list for both Washington and Oregon. Sale, purchase, and transport of plants, plant parts, and seeds is prohibited. Consult your local Noxious Weed Control Board for more information.
Buffalobur is commonly found on disturbed sites, waste areas, pastures, and similar sites. It is mostly found on sandy soils, but can adapt to many soil types.

Management Options

Non-Chemical Management
  • Cultivation (rototilling or hoeing) will effectively eliminate plants.
  • Mowing to prevent seed production is a very effective means of management. In lawns, mowing regularly at the proper height for the grass species may help minimize weed growth and invasion.
Select non-chemical management options as your first choice!

Chemical Management

Apply according to label instructions. Apply when seedlings are immature, prior to flowering. Apply glyphosate products as spot treatments only! NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas
  • glyphosate
Turf areas
  • 2,4-D + MCPP + dicamba
Bare ground areas
  • glyphosate
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Caption: Buffalobur with flowers
Photo by: D.G. Swan