Couch grass has creeping underground roots which are spread if rotovated. From the surface it looks like a clump of grass but underneath is a dense network of roots. Its wiry, underground stems and creeping shoots pop up around garden plants and before long can take over a flower bed.
Couch grass has flat, hairy leaves with upright flower spikes. The stems 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.
Insignificant flowers are produced in July / August time and these form seeds which can be spread by wind, water and carried on wildlife such as birds.
Couch Grass can be found in flower beds, paths and in the lawn.
Couch grass is susceptible to shade so can be killed by covering the area with old carpet. As a perennial weed thorough killing or eradication of its roots is necessary.
In uncultivated areas, forking out is possible in lighter soils, as much of the underground stem system is fairly shallow, but it is easy to leave behind small sections of rhizome in the ground. These quickly regrow and need to be removed before they form a new network of rhizomes.
In cultivated areas, hand weeding can be done where there are small isolated infestations among herbaceous perennials. This is best done in early spring when the plants will soon re-establish and around bulbs as the bulb foliage is dying, but is not practical around trees, shrubs and roses where roots may be considerably damaged.
Strip off infested lawns and dig out any remaining couch grass roots before re-turfing.
For harded infestations a glyphosate-based weedkiller can be effective but take care not to touch other plants with it.
A tea made from couch grass roots is useful for treating urinary infections because of the herb’s broad antibiotic, and diuretic properties. One of the chemical constituents, agropyrone, has been shown to have strong antibiotic properties. Couch grass tea will also soothe and coat an inflamed sore throat, and helps clear phlegm. The herb contains mucilage that helps to clear congestion while it coats the throat.