Scientific Name
Elymus repens (L.) Gould (Synonyms: Agropyron repens; Elytrigia repens)
Common Name(s)
Quackgrass, couchgrass
Tribe / Family Name
Triticeae
Flowering Period
June to August
Symbol
ELRE4
Description
Quackgrass is an introduced cool-season perennial rhizomatous grass that reproduces from seeds and aggressively spreading rhizomes; herbage is usually deep green or sometimes glaucous. Culms range from 50–100 cm in height. Its inflorescence is an erect spike 5–15 cm long with an internode space of usually 4–6 mm long and not shattering at maturity. Spikelets are 10–27 mm long, strongly imbricate, appressed along the rachis, 1 per rachis node, 4- to 7-flowered, and unawned or awned (the glume awns can be unawned or up to 3 mm long; the lemma awns can be unawned or up to 4 (10) mm long). Auricles are up to 1 mm long and clasping. Ligules are very short (up to 1.5 mm long), membranous, truncate, erose-ciliolate, and glabrous.
General Info
Quackgrass is drought-tolerant and can be found in disturbed moist areas including lawns, gardens, irrigation ditches, water courses, semi-wet meadows, irrigated pastures, roadsides, foothills, plains, and montane sites.
Similar Species
Quackgrass may look similar to other rhizomatous wheatgrasses such as intermediate wheatgrass (Thinopyrum intermedium), thickspike wheatgrass (Elymus lanceolatus ssp. lanceolatus), and western wheatgrass (Pascopyrum smithii). To distinguish it from these species, look for leaf veins of various spacing of quackgrass. Although, intermediate wheatgrass also has leaf veins of various spacing, quackgrass has strongly imbricate spikes with an internode space of usually 4–6 mm, while intermediate wheatgrass has non- or slightly imbricate spikes with an internode space of 7–12 mm.
Picture of growth habit.
Close-up picture of spike inflorescence.
Close-up picture of spikelet. The spikelets can either be unawned or awned. This example shows smaller awns.
Close-up picture of spikelet. The spikelets can either be unawned or awned. This example shows longer awns.
Close-up picture of short, membranous ligule and auricle.
Close-up picture of leaf veins of different heights.
Illustration of quackgrass. USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. <i>An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols</i>. Charles Scribner's Sons, New York. Vol. 1: 283.