Q What is couch grass?
Couch grass (Elymus repens) is a stealthy invader that creeps underground through tough, wiry rhizomes and can spread several metres in a season. It is also known as twitch grass.
Caption: Couch grass will resprout from any rhizomes left in the ground
Q Why is couch grass a problem weed?
A It can be tricky to get rid of because the rhizomes insinuate themselves between the roots and stems of established plants and into nooks and crannies at the bases of hedges, fences and walls. The rhizomes have sharp tips that can pierce other plants, plastic sheeting and even pond liners.
Q What is the best method for controlling couch grass?
A When Which? Gardening magazine trialled different methods for controlling couch grass, we found that glyphosate sprays wins hands down. Most of the couch grass was killed after one treatment of Roundup applied using the Hozelock Wonderweeder, hand-triggered spray or pumped spray. The glyphosate-sprayed plots remained largely clear of couch grass the following spring, too.
Q Are there concerns about glyphosate use?
A The main concern is that glyphosate can cause cancer. A second concern is the negative effect glyphosate use has on bee health. However it is legal to use. Find out more about glyphosate.
Q What is the best organic control for couch grass?
A For organic gardeners the best chemical-free method for controlling couch grass is digging it out by the roots. In our trial this was far better for reducing their number than pulling them up and a bit better than hoeing. Either way, the beds had more couch grass than glyphosate-treated ones the following spring.
Q Is glyphosate gel a good way to kill couch grass?
A Glyphosate gel reduces the amount of couch grass over the summer and the following spring, but was slower than sprays to work.
Q Is a weedkiller containing triclopyr effective for couch grass?
A Triclopyr, the selective weedkiller in Vitax SBK specifically targets broad-leaved weeds and is completely ineffective on couch grass.
Q Will a weed burner kill couch grass?
A Burning couch grass has little effect on controlling the number of weeds. It becomes unwise to try burning the couch as the grass dries out.