Larimer County Weed District Identification and Management of Common Cocklebur (Xanthium strumarium)
								Common cocklebur, also referred to as clotbur or sheepbur, is an annual in the sunflower family (Asteraceae) that is native to North America. Common cocklebur is found in disturbed areas, cultivated lands, degraded pastures, and lake shores. Cocklebur is most noted for the burs which contain the seeds. These burs readily attach to people and animals creating a particular problem in sheep country by degrading wool. In addition, the seedlings are extremely poisonous to livestock due to hydroquinone transmitted from the seed. An annual, such as cocklebur, is a plant that completes its life cycle in one season or one year. Annuals onlly produce by seeds. Therefore, the control of annuals should include the prevention of seed productions. Selective chemical control (only broadleaf plants are affected) of this plant can be achieved with products that contain 2,4-D such as 2,4-D Amine 4, Brash, Barrage, Curtail, Saber, and Turret. Non-selective control (all plants are affected) can be achieved with herbicides containing glyphosate such as RoundUp, Rattler, Razor, and Credit. Areas with a susceptibility of water contamination such as lake shores should be treated with herbicides with such as Rodeo or Eagre. See label for specific rates and timing of application. However, these herbicides, in general, are applied when the plant is actively growing; preferably when the plants are in the early bud stage. It is also recommended to use a surfactant when applying these herbicides. If you have any further questions, please contact our office at 970-498-5768.
			Common cocklebur shown above has rough leaves with wavy margins. The flowers of this plant are small, green, and inconspicuous. The burs are a clever mechanism for seed transport. Shown below are the burs attached to a shoe. The burs are approximately 1/3 to 1 inch long and contain two seeds, one of which usually germinates the first year after shedding and the other germinates the second year.

Top of Page

Back

Back to Weed District Home

Back to Parks & Open Lands Home