PO Box 419

Hotchkiss, CO 81419



fax: 720-880-3051




Elytrigia repens (L.) Nevski; Agropyron repens (L.) Beauv.


Keys to Identification

  • Spikelets of quackgrass are arranged in two long rows, and borne flatwise to the stem
  • Quackgrass leaves are often constricted near the tips

This information courtesy of the Colorado Natural Areas Program


Family: Grass (Poaceae)


Other Names: couchgrass




Legal Status: Colorado Noxious Weed List C (formerly List B)




Lifecycle: Perennial


Growth form: Grass


Flower: Slender spike, resembling wheat heads


Seeds/Fruit: Spikelets are arranged in two long rows, borne flatwise to the stem. Florets are awnless, or with short straight awns.


Leaves: Leaf blades are flat, pointed, 1/4 - 1/2 in wide, and have small ear-like appendages (auricles) at the junction of the blade and the sheath (Whitson et al 1996).


Stems: Mature plants are usually 1-3 ft tall and have erect stems.


Roots: Rhizomes are yellowish-white, sharp pointed, and somewhat fleshy.


Seedling: Both leaf sheath and blade are hairless or sparsely hairy. Clasping auricles and a short membranous ligule are present (Carey et al. 1993).




Agricultural: Quackgrass reduces productivity in crops, rangeland, and pasture


Ecological: Quackgrass is a rapid invader and quickly stabilizes moist eroding soils. It invades mixed-grass prairies, roadsides, ditches, crop fields, gardens, yards, and just about any disturbed, moist area. It is believed to be allelopathic (Whitson et al. 1996).



Habitat and Distribution

General requirements: Quackgrass is well adapted to moist soils in cool temperate climates. Optimum temperatures for growth are between 68 and 77 degrees F. Quackgrass is only moderately shade tolerant. Plant vigor is reduced when shading exceeds 50%.


Distribution: Quackgrass is widely distributed in North America. In Colorado, quackgrass is typically found between 4,800-10,000 feet.


Historical: Introduced from Europe



Biology/ Ecology

Lifecycle: Primary rhizome growth begins in early spring and then again in September and October with the onset of fall rains and cooler temperatures. Quackgrass flowers from June through August. Cross-pollination is necessary for seed production. Seeds germinate in fall or spring and plants are capable of producing seeds more than once per season.


Mode of reproduction: Quackgrass propagates mainly by rhizomes but also reproduces by seed.


Seed production: No information available


Seed bank: Seeds may remain viable for up to 10 years


Dispersal: No information available


Hybridization: Although quackgrass is considered an undesirable weed species it is often crossed with other wheatgrasses to create hybrids for grazing




Carey, J. Boyd, James J. Kells, and Karen A. Renner. 1993. Common Weed Seedlings of Michigan. Department of Crop and Soil Sciences Michigan State University Extension. Bulletin E-1363. Internet 10/27/99. Available:


FEIS - Fire Effects Information System [Online] (1996, September). Prescribed Fire and Fire Effects Research Work Unit, Rocky Mountain Research Station (producer), US Forest Service. Available: [1998,March 12]


Rutledge, Chris R. and Dr. Terry McLendon. No Year. An Assessment of Exotic Plant Species of Rocky Mountain National Park. Department of Rangeland Ecosystem Science, Colorado State University. 97pp. Northern Prairie Wildlife Research Center Home Page. (Version 15DEC98).


Whitson, T.D.(ed.), L.C. Burrill, S.A. Dewey, D.W. Cudney, B.E. Nelson, R.D. Lee, R. Parker. 1996. Quackgrass. Weeds of the West. Western Society of Weed Science, in cooperation with the Western United States Land Grant Universities Cooperative Extension Services, Newark CA. pg. 411.



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