Couch grass is a fast-growing perennial that can reach up to 1m (3½ft) tall. Its stems hold flattened green leaves up to 40cm long, the lower ones partially covered with a pale sheath. Upright, unbranched flower spikes appear in late summer; these feel smooth to the touch as flower buds are held flat to the stem. The tiny flowers are yellowish-green. Golden seeds follow in early autumn.  

Underground, couch grass produces thin, fibrous feeding roots and a dense network of pale

Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

Couch grass has long been considered a weed by gardeners as, unlike other coarse grasses, it often grows among and through border plants as well as in lawns and on allotments. Those wishing to maintain immaculate, uniform lawns and tidy borders are likely to want to remove couch grass before it becomes established and spreads.  

However, couch grass is an important source of food for butterfly and moth caterpillars, including those of speckled wood and ringlet butterflies. Its swaying flower and seed heads also look attractive when grown in a meadow or species-rich lawn. As gardeners embrace “ecological gardening” and welcome a wider range of species into their gardens, couch grass is increasingly seen as a wildflower.

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Caterpillars of ringlet butterflies feed on couch grass 

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Couch grass flowers are an attractive addition to meadows

Here are our answers to your most common questions about dealing with couch grass: 

How invasive is couch grass? 

Couch grass didn’t earn its reputation as a weed for nothing – it spreads quickly once established. Plants come into growth and begin sending out new rhizomes in early spring, allowing it a head start on many other garden plants. These rhizomes root and send up a tuft of new growth as soon as they find a suitable patch of bare ground. Established plants also produce seed in early autumn, and these can remain viable in the soil for years until conditions favour germination. 

The good news is that couch grass isn’t deep rooting and seedlings or new plants are easily removed if spotted early. Plants also produce a relatively low number of seeds, approximately 30 per flower stem, and only around half of these are usually viable. Finally, as regular mowing tends to suppress its growth in lawns, couch grass can grow happily alongside other lawn grasses without taking over.

Do I need to get rid of couch grass? 

Not necessarily – allowing couch grass to grow in a meadow, species-rich lawn, on a steep bank or in a wildlife patch or uncultivated area is a great way to support wildlife and boost the biodiversity of your garden.

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A patch of couch grass and nettles will attract butterflies and moths 

What is the easiest way to kill couch grass? 

If you have couch grass growing where it is not wanted, there are a few ways to remove it: 

In borders 

• Avoid disturbing the soil – couch grass can regenerate from rhizome fragments, so avoid chopping them up by hoeing or digging over the soil where it grows.  
• Fork out individual plants – use a hand fork to tease couch grass and its roots and rhizomes from the soil. It’s often easiest to grasp a shoot and fork round it, gently lifting to reveal the roots that need to be dug out. This is best done in early spring before new couch grass plants become established and before established ones send out new rhizomes. Check for regrowth regularly throughout the growing season. 
• Lift border plants, clear the ground and replant – an option where couch grass is abundant in established borders and you don’t wish to leave the area bare (as below). Use a border fork to lift out and set aside border plants and then remove as much couch grass as possible. Take the time to work right through the area, teasing out as many rhizomes as you can find. Before replanting, examine the rootballs of your plants carefully to remove any hidden couch grass rhizomes. This is best done in early spring, when new couch growth is easy to spot and border plants are only just starting into growth. Fork out regrowth (as above) throughout the growing season as soon as it appears. 
• Cover the soil to smother growth – a good option where couch grass is abundant in as yet uncultivated areas. Cut down couch grass stems, cover the ground with a layer of compostable material, such as cardboard, and cover that with a layer about 20cm (8in) thick of organic matter, such as bark or wood chips. Alternatively, use a heavy grade biodegradable mulch matting. This will block out light and prevent growth, causing the root system to die. Leave in place for at least a few years, topping up the organic matter layer as necessary.

Teasing out couch grass with a hand fork is a good way to remove individual plants from beds and borders

 In lawns 

• Improve the health of your lawn – couch grass is less able to spread into and establish in dense, healthy lawns. Follow a programme of lawn maintenance in spring/summer and autumn to boost the vigour of your lawn. If patches of your lawn are struggling, overseed with a mix to suit the growing conditions.   
• Mow regularly – this will prevent couch grass from flowering and setting seed, helping to curtail its spread.  
• Fork out individual plants and repair bare patches – use a hand fork to lift couch grass plants and their rhizomes from the lawn. September is a good month to carry this out, as you can re-seed bare patches straight away. This is a good, easy option for quick results on small areas of lawn. Where couch is widespread within a lawn and cannot be tolerated, it may be necessary to strip off the turf, dig out the couch grass and re-lay or reseed the lawn.

  Top Tip

  Don’t add rhizomes, roots or seed from couch grass to your home compost bin, as it may not reach high enough temperatures to kill them. Instead, put them in your council green waste recycling bin or take them to your local recycling site.

Should I use weedkiller?  

No – although time consuming, couch grass can be controlled naturally, so there is no need to use a weedkiller. As couch grass is a grass species, there are no selective lawn weedkillers available that will kill it without also harming your lawn grass.  

For more information see our page on Weeds: non-chemical controls.