Agropyron repens, a perennial grass that is an invasive weed in lawns and gardens. It is also called Dog Grass, Twitchgrass, Witch Grass, Quitch Grass and Quackgrass or Quack Grass.
Or Dog Grass as it is known because dogs, when they do not feel well or have a stomach ache will seek it out; Couch Grass is diuretic or has diuretic properties.