Couchgrass
(Dog's Grass, Twitch)
(Agropyrum repens, syn. Elymus repens)

Perennial, creeping underground stems with small fibrous roots at every joint. Sweet taste. Increases urinary production, is soothing and has antibiotic properties, so it is used for cystitis and other inflammatory urinary tract diseases. Flowers May to October, producing green herringbone-like seed-heads Height up to 1 metre.
Difficult to eradicate by cultivation, but repetition will eventually exhaust the perennial root system. Dig out as much as possible, use a fork to avoid chopping up the stems a small fraction of which will regrow. If any do regrow carefully tease them up with a hand fork. Weedkillers to use:-
Glyphosate, systemic action, taken down into underground parts.