Elymus repens is a rhizomatous perennial grass that grows up to 1.2m tall. The stems (culms) are erect and more or less curved at the base, hollow, and green to whitish in color.
The grass is easily recognizable by its linear, dark green leaves with small auricles at the base and elongated pale greenish wheat-like spikelets arranged in two long rows.
Elymus repens Classification
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Monocotyledonae
- Order: Cyperales
- Family: Poaceae
- Genus: Elymus
- Species: Elymus repens
- Common Names: Couch grass, Creeping wheatgrass, Dog grass, Quick grass, Quitch, Quitch grass, Scutch, and Scutch grass.
Nativity and Distribution
Common Couch is native to Europe and temperate Asia. It is now also found in:
- Northern Africa
- North America
- Central and South America
- Pacific Islands
Physical Characteristics
- Leaves: Linear, flat, leaves about 15 to 40 cm long.
- Stems: Erect, hollow, green to whitish.
- Flowers: Slender pale to greenish wheat-like spikelets.
- Roots: Fibrous root system.
Elymus repens is a rhizomatous perennial cool-season grass that grows 30-120 cm tall. It is easily recognizable by its linear, dark green leaves with small auricles at the base and elongated pale greenish wheat-like spikelets arranged in two long rows.
The stems (culms) are generally erect and hollow and green to whitish in color. The leaves are linear, flat, dull to dark green, about 3-10mm wide and 15-40 cm long with auricles in the sheath and blade intersection. On the upper surface, they are generally slightly hairy or smooth while the lower surface is strongly hairy.
Quackgrass produces wheat-like flower spikes that contain 5-15mm long spikelets. The spikelets bear 4-6 flowers. Flowering occurs between May and September.
The seeds are elliptical, brown, confined in lanceolate and awn-pointed glumes.
Reproduction, Dispersal, and Life Cycle
- Life Cycle: Perennial.
- Seeds: One stem typically produces 20-40 seeds but can produce up to 400.
- Climate: Temperate and cool climatic conditions.
- Dispersal: Wind, water, animals, and human activities.
Elymus repens, behaves as a perennial and reproduces sexually through seeds and asexually through rhizomes. One stem typically produces 20-40 seeds with a dormancy range of about 2-5 years.
The seeds are small and lightweight with bristle-like appendages that aid in wind dispersal. Secondary dispersal also occurs through water, animals, and human activities.
While seeds play a critical role in establishing a new grass population, especially after effective weed control, they are not the primary method of propagation.
Rhizomes (even small fragments with a node) allow for faster propagation in new areas by rapidly developing extensive clones, contributing to its nature as an aggressive weed. Soil cultivation often breaks both rhizome and seed dormancy, causing rapid spread of the grass.
Similar Plants
- Elymus trachycaulus
- Cynodon dactylon
- Agropyron cristatum
- Poa pratensis
Uses
- In its early growth, it is used as forage in pastures and fodder for livestock.
- Its extensive root system is used in soil stabilization and erosion control.
- The rhizomes have been used as traditional medicine for fever in Austria. It is also a favorite stomach upset medicine for cats and dogs.
- Different forms of the root are used to make bread and beer. Young shoots are incorporated into spring salads.
- It provides habitat for birds and small mammals.
Impact on Farms and Environment
Quackgrass is considered a serious weed in agricultural regions worldwide. Its rapid and extensive growth affects a variety of crops including cereals, fruits, and grasslands. Not only does it compete for important nutrients leading to reduced crop yield but it also causes technical problems during harvest.
Removing the grass by hoeing is often difficult when the rhizomes become entangled in the annual crops and other perennial weeds. This makes removal efforts time-consuming and expensive. Its ability to regenerate from severed fragments also makes it difficult to eradicate.
Due to its rapid growth, the common couch can colonize large areas and outcompete native species, negatively impacting biodiversity.
Control
- Cultural control: Crop competition.
- Mechanical control: Intensive cultivation
- Chemical control: Herbicides like glyphosate, tepraloxydim, cycloxydim, and EPTC.
Cultural control is generally the first line of defense against quackgrass. Well-prepared ground and planting the crop seeds at optimal depth can help increase the plant’s competitiveness against the grass.
Cultivation can offer additional control when done starting immediately after crop harvest. Repeated operations break the rhizomes down as much as possible. Ploughing just before planting can suppress the weed by up to 90%.
However, the best way to control Elymus repens is by herbicides. Selective herbicides like tepraloxydim, cycloxydim, sethoxydim, and foliar-herbicides like sulfuron are used in turnip, peas, beet, cereals, and orchard farms.
Glyphosate, a non-selective herbicide, also provides effective common couch control in many countries.
Consult a professional if you’re unsure of the herbicide to use for quackgrass control on your farm or landscape.
Lead Editor for Insight Weeds.