Ohio Perennial and Biennial Weed Guide

Family: Grass Family (Gramineae)

Other Names: Agropyron repens, Elymus repens, Triticum repens, couch grass, devils-grass, knot-grass, quick grass, quitch grass, scutch-grass, twitch, wheat grass.

Origin and Distribution: Quackgrass is a native of Europe, but has spread throughout the northern temperate zones of the world. It is primarily found in the northern portion of the U.S., and is common throughout Ohio. According to a botanical publication from 1672, it was introduced into New England by the colonists for forage. Quackgrass is typically found in crop fields, roadsides, river banks, lawns, waste places and abandoned fields. It is often used for hay and pasture. This species can grow in a variety of soil types, and has a high tolerance for drought and salinity. It prefers neutral to alkaline soils.

Plant Description: Quackgrass is a creeping, sod-forming perennial grass, characterized by its straw-colored, sharp-tipped rhizomes (horizontal underground stems) and the pair of whitish-green to reddish, claw-like structures (auricles) that clasp the stem at the top of the sheath. It reproduces through seed and creeping rhizomes. This species can form large patches.

Root system - The slender, extensively spreading rhizomes (horizontal underground stems) are white to pale yellow, with brownish sheaths at the joints (nodes), giving them a scaly appearance. Tips of the rhizomes are sharply pointed. Rhizomes can grow 3 to 11 feet long, and form a dense mat. Most rhizomes are found within 4 to 6 below the soil. Fibrous roots are produced at the nodes.
Stems - Stems are erect, smooth, round and unbranched. They can grow 1 to 4 feet tall and, like most grasses, are hollow.
Leaves - Leaves are rolled in the bud. The leaf blade (free part of the leaf) is dull grayish-green (sometimes dark green), thin, flat and finely pointed. Blades are finely ribbed on upper and lower surfaces, and measure 1 1/2 to 8 inches long (sometimes up to 12 inches) and 1/8 to 1/4 inch wide (sometimes up to 1/2 inch). The upper blade surface and margins are typically rough or slightly hairy, and the lower surface is smooth. The base of the blade is often lighter in color. The leaf sheath (part of the leaf surrounding the stem) is round and short, with overlapping margins. Lower sheaths are usually hairy, while the upper sheaths are smooth. The ligule (projection inside on the top of the sheath) is membranous and very short (1/50 to 1/25 inch long). A pair of whitish-green, brownish or reddish, narrow, claw-like appendages (auricles) clasp the stem at the junction between the leaf blade and sheath.
Flowers - Flowers are arranged in a long, slender, unbranched spike (2 to 10 inches), resembling a slender head of wheat.
Fruits & Seeds - The yellow-brown seeds (1/5 to 1/3 inch long) are elongated toward the tip, tapering to a blunt base, and topped with a ring of hairs.

Similar Species: Quackgrass may be confused with tall fescue (Festuca arundinacea) and smooth brome (Bromus inermis). However, both of these species lack the long appendages (auricles) which are present at the junction between the leaf blade and sheath in quackgrass.

Biology: Seeds of quackgrass germinate in early spring, and flowering occurs from late May to September. Flowers are wind-pollinated and relatively self-sterile. One quackgrass plant can produce up to 400 seeds per season, but most plants produce fewer than 50 seeds. Seeds are short-lived, and are reported to lose viability within 4 years. Seeds have been found to remain viable after passing through the digestive tracts of horses, cows and sheep, but not after passing through pigs.

This weed species can form large patches. A single plant is capable of producing a system of rhizomes extending 11 feet in diameter (over 440 feet of rhizomes), with more than 200 aerial shoots. Rhizomes are generally found in the top 4 to 6 inches of soil, with those in the top 1 to 3 inches of the soil profile being the most productive. Rhizome tips are very sharp and capable of piercing roots and tubers of desirable plant species. New plants can be formed from cut sections of rhizomes containing a node.

Quackgrass is a troublesome weed in 32 crops in over 40 countries. Interference of this species with crops can cause yield reductions (up to 85% in corn) and can also result in delayed corn maturity. It is an alternate food source for several insect and disease pests of grain, such as the cereal leaf beetle (Oulema melanopa) and bromegrass mosaic virus. Regular chopping of rhizomes through cultivation can be an effective way of controlling quackgrass infestations. However, research has found that 30% of 1/8 inch fragments of quackgrass rhizomes were capable of producing aerial shoots. Repeated tillage from August until the ground becomes frozen is reported to give good control. Also, repeated cropping of rye or buckwheat is thought by some to help eliminate quackgrass. Addition of compost or calcium, combined with aeration, are other suggested nonherbicide control methods.

Quackgrass has valuable uses. It remains green all year round and can make good forage and hay. Total crude protein content is comparable to timothy (Phleum pratense). Nitrogen levels in quackgrass are high enough, without reaching toxic levels, to be appropriate for cattle feed, although biomass productivity and palatability are generally low. Quackgrass can be used to prevent soil erosion, and it is effective in removing nutrients from wastewater effluent when sprayed on soil.

Toxicity: None known. Wind-blown pollen can contribute to hayfever.

Facts and Folklore:

The name 'quack' is a variation of the German 'quecke', which means 'to live', referring to the persistent nature of this weed.

Native Americans used the rhizomes of quackgrass as a diuretic. Rhizomes are high in minerals and vitamin B1, and can be dried and ground for flour.

In Tanzania, quackgrass has been used to prevent arrow poisoning by placing moistened plant material on the wound.

A methanol extract made from quackgrass has been used to control mosquito larvae.