Photo Courtesy of Steve Dewey, Utah State University, bugwood.org
Taeniatherum caput-medusae (L.) Nevski
Scientific Name Synonyms:
Elymus caput-medusa L.
Taeniatherum asperum auct. Non (Simonkai) Nevski
Taeniatherum crintinum (Schreb.) Nevski var. caput-medusae (L.) Wipff
Life Span: Annual
Growth Characteristics: Medusahead is an extremely competitive grass, completely displacing other desirable grass species. It grows from 6 inches to 2 feet high, producing tillers but very few leaves. Flowering and seed production take place in late spring or early summer, usually 2 to 4 weeks later than most annual grasses. It spreads by seed which is commonly carried by wind, animals, clothing, and vehicles.
Seedhead: Awns of the seedhead are 1 to 3 inches long, stiff, and minutely barbed. They become twisted as the seed matures, in a manner reminiscent of the snake-covered head of the mythic Medusa. The seedhead doesn’t break apart completely once the seeds mature, unlike squirreltail or foxtail barley. It produces an average of 7 seeds per spike.
Leaves: Leaf blades are about 1/8 inches wide and rolled.
Stems: 6 to 24 inches tall.
Medusahead grows in areas that have relatively mild to cold temperatures in winter but are hot in summer. It is generally found in areas that receive fall, winter, and spring moisture, followed by dry summer. It occurs in areas with annual precipitation of 10-40 inches. Infestations primarily occur in former sagebrush-grass or bunchgrass communities that receive 10 to 20 inches of precipitation.
Soils: It often dominates disturbed areas on soils with high moisture-holding capacitities and slow percolation rates.
Associated Species: Cheatgrass, Russian thistle, tumblemustard
Uses and Management:
The introduction and subsequent rapid spread of medusahead has caused serious management concern because of its rapid migration, vigorous competitive nature, and low forage value. Control of it with herbicides has had limited success. Mowing alone, or in combination with grazing, has been found to be effective in reducing infestations. Plowing and disking are also effective.
The barbed awns of medusahead can cause injury to the eyes, noses, and mouths of grazing animals. It has little to no feed value at any stage of growth, but it has been noted that livestock utilize it when other feed is limited.
A healthy stand of perennial vegetation appears to be the best barrier to medusahead invasion. Medusahead invasions are most common on ranges in poor condition. Poor grazing management practices may accelerate the rate of spread, but proper management alone may not prevent invasion. Cultivated areas are susceptible to invasion by medusahead, especially old fields.