Elymus repens, commonly known as couch grass , is a very common perennial species of grass native to most of Europe, Asia, the Arctic, and northwest Africa. It has been brought into other mild northern climates for forage or erosion control, but is often considered a weed.
Other names include common couch, twitch, quick grass, quitch grass (also just quitch), dog grass, quackgrass, scutch grass, and witchgrass.
Description
It has creeping rhizomes which enable it to grow rapidly across grassland. It has flat, hairy leaves with upright flower spikes. The stems ('culms') grow to tall; the leaves are linear, long and broad at the base of the plant, with leaves higher on the stems broad. The flower spike is long, with spikelets long, broad and thick with three to eight florets. The glumes are long, usually without an awn or with only a short one.
It flowers at the end of June through to August in the Northern Hemisphere.
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File:Elymus.repens.jpg|Flower spike
Image:Kweek ligula Elytrigia repens.jpg|Blunt ligule 1 mm high, also showing a few very fine hairs of the plant
Image:Kweek blad Elytrigia repens.jpg|Showing the leaf is dull green, mainly parallel, with auricles and ribbed
Image:Kweek rizomen Elytrigia repens.jpg|Rhizomes
Image:Kweek Elytrigia repens.jpg|General appearance of the plant including tuft shape
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Taxonomy
Various taxonomic subdivisions of this species have been proposed. Moreover, it is assigned to various genera (Elymus, Elytrigium, Agropyron). In a recent classification, three subspecies are distinguished, one of these with an additional variety: The caterpillars of some Lepidoptera use it as a foodplant, e.g. the Essex skipper (Thymelicus lineola).
Eradication
Couch grass has become naturalised throughout much of the world, and is often listed as an invasive weed. Another method is to dig deep into the ground in order to remove as much of the grass as possible. The area should then be covered with a thick layer of woodchips. To further prevent re-growth, cardboard can be placed underneath the woodchips. The long, white rhizomes will, however, dry out and die if left on the surface. Many herbicides will also control it.
Applications
The dried rhizomes of couch grass were broken up and used as incense in medieval northern Europe where other resin-based types of incense were unavailable. Elymus repens (Agropyron repens) rhizomes have been used in the traditional Austrian medicine against fever, internally as a tea, syrup, or cold maceration in water, or externally applied as a crude drug.
References
External links
- Species Profile- Quackgrass (Elymus repens), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Quackgrass.