Dog Grass (Couch Grass) Root also known as Agropyron repens, Elymus repens, couchgrass, quackgrass, quickgrass, twitchgrass, Agropyron firmum, Couch Grass, Cutch, Dog Grass, Dog-grass, Doggrass, Durfa Grass, Elymus repens, Elytrigia repens, Graminis rhizoma, Quitch Grass, Scotch Quelch, Triticum firmum, Triticum repens, Wheat Grass, Witch Grass. Famous herbalist Nicholas Culpeper wrote that "although a gardener may be of another opinion, a physician holds that a 1/2 acre of dog grass to be worth 5 acres of carrots twice told over." Dog grass is an invasive grass that grows well in regions with warm summers and cool or cold, damp winters. Its name is derived from the simple fact that dogs will eat the grass when they are sick to induce vomiting and cool the blood. Couch contains agropyrene (bactericidal), calcium, fructosan, magnesium, manganese, mannitol, mucilage, phosphorous, potassium, selenium, silicon, sodium, tin, triticin, zinc.