Elytrigia repens (Couch Grass; syn. Triticum repens L., Agropyron repens (L.) P. Beauv., Elymus repens (L.) Gould) is a very common species of grass native to most of Europe, Asia, and northwest Africa. Other names include twitch, quick grass, quitch grass, dog grass, and quackgrass.
It has creeping rhizomes which enable it to grow rapidly across grassland. The stems ('culms') grow to 40–150 cm tall; the leaves are linear, 15–40 cm long and 3–10 mm broad at the base of the plant, with leaves higher on the stems 2–8.5 mm broad. The flower spike is 10–30 cm long, with spikelets 1–2 cm long, 5–7 mm broad and 3 mm thick with three to eight florets. The glumes are 7–12 mm long, usually without an awn or with only a short one.
There are three subspecies, one of these with an additional variety:
- Elytrigia repens subsp. repens. Throughout most of the range of the species.
- Elytrigia repens subsp. repens var. repens. Awns usually absent or if present, very short.
- Elytrigia repens subsp. repens var. aristata (Döll) P.D.Sell. Awns present, up to 15 mm long.
- Elytrigia repens subsp. elongatiformis (Drobow) Tzvelev (syn. Elytrigia elongatiformis (Drobow) Nevski). Central and southwestern Asia, far southeastern Europe (Ukraine).
- Elytrigia repens subsp. longearistata N. R. Cui. Western China (Xinjiang).
Hybrids are recorded with several related grasses, including Elytrigia juncea (Elytrigia × laxa (Fr.) Kerguélen), Elytrigia atherica (Elytrigia × drucei Stace), and with the barley species Hordeum secalinum (× Elytrordeum langei (K. Richt.) Hyl.).
The foliage is an important forage grass for many grazing mammals
. The seeds
are eaten by several species of grassland birds
, particularly buntings
. The caterpillars
of some Lepidoptera
use it as a foodplant, e.g. the Essex Skipper
Cultivation and uses
Couch Grass has become naturalised
throughout much of the world, and often listed as an invasive weed
. It is very difficult to remove from garden environments. One 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.
Couch Grass has been used in herbal medicine
since the Classical Greek
period. Sick dogs are known to dig up and eat the root, and mediaeval herbalists
used it to treat inflamed bladders
, painful urination and water retention
. It also has antiseptic properties.
The dried rhizomes
of couch grass were broken up and used as incense
in mediaeval Northern Europe where other resin-based types of incense were unavailable.
Notes and references