Quackgrass: How to Identify and Control It
Elymus repens · Perennial grass
How to identify quackgrass
- Bluish-green blades with a slight constriction near the tip
- Small claw-like auricles that clasp the stem
- Long, white, sharp-tipped rhizomes
- Narrow, wheat-like seed spikes
Why it shows up
A cool-season perennial grass spreading by aggressive rhizomes, especially in the northern US. Tilling chops rhizomes into pieces that each regrow.
Where it's a problem
- Northeast & Mid-Atlantic (zones 4–8) — Common in New England and New York gardens.
- Midwest (zones 4–7) — One of the toughest perennial grass weeds in northern Midwestern gardens.
- Great Plains & Texas (zones 3–9)
- West & Pacific Northwest (zones 3–10 (1–8 in Alaska))
Control methods
1. Cultural (prevention)
- Don't till infested soil without a control plan
- Smother before planting new beds
2. Mechanical
- Dig out rhizomes thoroughly; repeated digging weakens patches
3. Organic options
- Cover with black plastic or cardboard and mulch for a full season
4. Chemical options
Herbicide safety — always follow the label. The label is the law: use only products labeled for your site, turfgrass or crop, and follow rates, timing, weather limits and protective equipment directions exactly. Keep people and pets off treated areas as directed, and check state and local rules. Active ingredients named here are examples from extension guidance, not endorsements; availability varies by state.
- No selective option in cool-season lawns: spot-treat with glyphosate (it kills turf too), then reseed
- In beds, grass-selective herbicides such as sethoxydim or clethodim where labeled
When to treat quackgrass by USDA zone
| USDA zone | Typical timing (from NOAA frost-date medians) |
|---|---|
| Zone 3 | Best: Aug 19 to Oct 7 (fall, around the first frost on Sep 23); a second option is spring after full green-up (from ~Jun 7) |
| Zone 4 | Best: Aug 26 to Oct 14 (fall, around the first frost on Sep 30); a second option is spring after full green-up (from ~May 31) |
| Zone 5 | Best: Sep 2 to Oct 21 (fall, around the first frost on Oct 7); a second option is spring after full green-up (from ~May 24) |
| Zone 6 | Best: Sep 14 to Nov 2 (fall, around the first frost on Oct 19); a second option is spring after full green-up (from ~May 17) |
| Zone 7 | Best: Sep 23 to Nov 11 (fall, around the first frost on Oct 28); a second option is spring after full green-up (from ~May 2) |
| Zone 8 | Best: Oct 6 to Nov 24 (fall, around the first frost on Nov 10); a second option is spring after full green-up (from ~Apr 14) |
| Zone 9 | Best: Oct 27 to Dec 15 (fall, around the first frost on Dec 1); a second option is spring after full green-up (from ~Mar 16) |
Zones 10–11 (frost rare): follow germination flushes after rains; pre-emergents in late summer/fall for winter weeds and late winter for summer weeds. Find your exact frost dates with the ZIP planner. Soil temperature and the product label take priority over the calendar.
Frequently asked questions
How do I get rid of quackgrass naturally?
Start with cultural and mechanical controls: Don't till infested soil without a control plan; Smother before planting new beds; Dig out rhizomes thoroughly; repeated digging weakens patches.
What does quackgrass look like?
Bluish-green blades with a slight constriction near the tip; Small claw-like auricles that clasp the stem; Long, white, sharp-tipped rhizomes; Narrow, wheat-like seed spikes.
When is the best time to treat quackgrass?
Fall, from about a month before to two weeks after your first fall frost, is usually most effective because plants move sugars (and herbicide) down into their roots.
Where is quackgrass a problem in the US?
Quackgrass is common in: Northeast & Mid-Atlantic, Midwest, Great Plains & Texas, West & Pacific Northwest.
Sources & further reading
- UC IPM (University of California) weed gallery: weed photo gallery
- Tardif et al. (1993). Translocation of Glyphosate, Quizalofop, and Sucrose in Quackgrass (Elytrigia repens). Weed Science. doi:10.1017/s0043174500052036
- Herbicide examples are typical active ingredients named in university extension guides; products and registrations vary by state. See your state Cooperative Extension weed-control guide.
Related weeds in the same regions
Crabgrass · Dandelion · White Clover · Field Bindweed · Yellow Nutsedge · Common Chickweed · Broadleaf Plantain · Creeping Charlie (Ground Ivy) · All 27 weeds
Planning a garden? See planting calendars by state & zone.