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Taeniatherum caput-medusae - Poaceae Family

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  • Flowers:  Flowers are long awned and barbed at the end.  Over time they become twisted and are reminiscent of the snake-haired Medusa of Greek mythology.
  • Seeds:  Often confused with foxtail barley, Medusahead seed heads do not break apart as the seed matures.
  • Leaves:  Stems are wiry with a few short leaves that are somewhat rolled.
  • Flowering Time:  Germinates in the fall and, lives dormant over the winter, and sets seed in the spring.
  • Life cycle:  A winter annual ranging from 6-24 inches in size.  Medusahead prefers clay soil, because of its ability to hold moisture late in the season when fall germination takes place. 


  • Invades grasslands and rangelands, and can reduce the carrying capacity for domestic livestock up to 75%.
  • The barbs can puncture grazing animals and are easily transported because of their ability to cling to the feet and fur of humans and animals.
  • It is extremely competitive and can form dense stands as thick as 100 plants per square foot, transforming entire ecosystems.


Most effective control methods

  • No one method will eradicate Medusahead, and it is very important to incorporate revegetation into long term management plans.
  • For larger infestations, disking or plowing, chemical applications, and burning has proven to be the most effective combination of methods.
  • Because of its life cycle, control measures are most effective when implemented in both the fall as a preemergence, and the following early spring as a post emergence.
  • Herbicide applications including Plateau, Roundup and Landmark applied in the fall preemergence or very early post emergence in the spring can provide control greater than 90%.


Large Images


Steve Dewey, Utah State University,




Chris Evans, University of Illinois,

Medusahead: flowers



Steve Dewey, Utah State University,

Medusahead: flowers



Leslie J. Mehrhoff, University of Connecticut,

Medusahead: fruits



Steve Dewey, Utah State University,

Medusahead: fruits



Steve Dewey, Utah State University,




John M. Randall, The Nature Conservancy,

Medusahead: infestation



Steve Dewey, Utah State University,

Medusahead: seeds


  • Medusahead Fact Sheet

  • References

    Davies, K., Nafus, A., & Johnson, D. Interim medusahead management guide for the intermountain west [PDF file]. Retrieved from 

    DiTomaso, J.M., G.B. Kyser et al. (2013). Weed Control in Natural Areas in the Western United States [PDF file]. Weed Research and Information Center, University of California. Retrieved from View PDF

    Kyser, G., DiTomaso, J., Davies, K., Davy, J., & Smith, B. (2014). Medusahead Management Guide for the Western States [PDF file]. Retrieved from View PDF

    M.E. Stannard, D.O. Ogle, & L. St. John. (2010). Plant guide for medusahead (Taeniatherum caput-medusae) [PDF file]. Retrieved from View PDF

    Washington State Noxious Weed Control Board. Medusahead. Retrieved from

    Washington State University. (2009). Medusahead. Retrieved from