- Various types: Common cocklebur, spiny cocklebur
- Scientific name: Xanthium strumarium1
- Grass or broadleaf: Broadleaf1
- Found in: AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY2
- Germination timing: Seeds germinate from early spring through summer from depths of up to 6 inches. Be wary: The seeds and small seedlings are toxic to humans and livestock, although toxicity decreases rapidly as the first true leaves develop. Seeds are about ½ inch long and 1½ inches wide. Cocklebur will flower from August through October.2
- Competitiveness: Mature burs are spread primarily by humans and animals. The spiny burs contribute to the spread of cocklebur and make it difficult to control. It is competitive in most crops, especially in soybeans because of its similar emergence time and growth habit.2
- The stem below the cotyledons is purple at the base and green in the upper portion. The first true leaves are opposite, while all subsequent leaves are alternate. The large, linear, oblong waxy cotyledons distinguish this weed in the early stages of development.3
- The flower heads of common cocklebur are unisexual. Small male and female flowers form separate clusters.2
- The distinct seed pods, or burs, make cocklebur easy to identify. Burs are light brown, long and oval or oblong.2
According to WeedScience.org:
- Herbicide classes
*Resistance confirmation does not necessarily include all weeds and may vary among different areas of each state.
Weed management tips:
Scott Ditmarsen, field scientist, Dow AgroSciences, says:
- Cocklebur occurs across the central and southern crop production areas.
- Many soil-applied herbicides are relatively ineffective in controlling cocklebur. Postemergence herbicide applications often are required for effective control.
- Scouting must be done early enough to allow timely application of postemergence herbicides.
Dow AgroSciences weed control solutions:
More information can be found through these weed science resources: