Quackgrass, a creeping perennial, is a very aggressive grass and is considered a noxious weed in Colorado. It spreads by seeds and invasive rhizomes (underground stems). Its rhizomes are yellow-white, with brown sections, and the ends are sharp-pointed.
A few quackgrass plants can be spot-sprayed with glyphosate, or individual blades can be painted with glyphosate. Note that glyphosate will kill any bluegrass it contacts. Repeat applications to quackgrass will likely be needed.
Renovate severely infested lawn areas. Spray with glyphosate; repeat applications will likely be needed. When the quackgrass has been killed, the areas may be resodded or reseeded. Always read the label before applying any pesticide.
Photographs courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010