Plant Problem Diagnostic
How to Identify and Control Quackgrass
The short answer
Quackgrass (Elymus repens) is a persistent perennial grass that spreads by both seed and long, creeping rhizomes, forming dense clumps. Identify it by narrow, flat leaf blades with rough upper surfaces, clasping auricles that wrap the stem, and long, slender, white to pale-yellow rhizomes with sharp pointed tips.
Those far-reaching rhizomes make it hard to remove. Dig and carefully remove all the rhizomes to eliminate single plants and small patches, and use repeated cultivation to cut them up, because any fragment left in the soil can start a new plant.
How to identify quackgrass
- Perennial grass spreading by seed and rhizomes
- Narrow, flat leaves with rough upper surfaces
- Clasping auricles that wrap around the stem (key trait)
- Long, slender, white to pale-yellow rhizomes with sharp tips
Cultural and physical control
For single plants and small infestations, dig and carefully remove all the rhizomes. Repeated cultivation to expose and cut up the rhizomes has been effective in some situations, and repeated mowing can substantially reduce rhizome biomass over time. Be thorough, since fragments regenerate.
When to escalate
Quackgrass often outlasts partial digging because of its extensive rhizomes. If it persists or covers a large area, escalate your plan. For chemical control options and appropriate timing in your area, consult your county Extension office.
→ For chemical control options, contact your local county Extension office; note selective options in lawns are limited because quackgrass is a grass.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Washington State University Hortsense — Quackgrass — Perennial spreading by seed and rhizomes, clasping auricles, long white sharp-tipped rhizomes, dig out all rhizomes for single plants/small infestations
- Iowa State University Extension — Quackgrass — Rhizomes long-lived, slender, white with sharp tips, produce new roots and shoots every few inches; repeated cultivation cuts them up