Quackgrass
Elymus repens
Quackgrass (Elymus repens) is a perennial grassy weed characterized by coarse bluish-green blades; clasping claw-like auricles; sharp, white creeping rhizomes capable of piercing roots.. It anchors via a creeping stolons root system and is selectively controlled using Non-selective Glyphosate spot treatment (few selective options exist in cool turf) applied during spring or early fall when quackgrass is 6–8 inches tall and actively growing..
Non-selective Glyphosate spot treatment (few selective options exist in cool turf)
Coarse bluish-green blades; clasping claw-like auricles; sharp, white creeping rhizomes capable of piercing roots.
Always read and follow the manufacturer's EPA-approved pesticide product label. The label is the law under federal FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act) regulations. Application rates, personal protective equipment (PPE), target weed maturity stages, temperature restrictions, and grazing or re-entry intervals specified on the EPA container label supersede all online recommendations. Local state regulations may restrict certain active ingredients.
University-Verified Herbicide Formulations
Professional active formulations cross-referenced against university weed science trials.
Tenacity Herbicide (Mesotrione 8 oz)
Active: 40% Mesotrione Selective Systemic
Gold standard selective pre- and post-emergent targeting crabgrass, ground ivy, yellow nutsedge, and clover during overseeding.
SedgeHammer+ Turf Herbicide (Halosulfuron 0.5 oz)
Active: 5% Halosulfuron-methyl with Surfactant
Pre-mixed with surfactant for 1-gallon sprayers. Translocates into underground nutlets without injuring cool or warm season lawns.
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Botanical Identification Key for Quackgrass
Accurately identifying Elymus repens is essential because spraying non-selective chemicals like glyphosate risks killing desirable lawn grass. Look for these botanical hallmarks:
- Foliar Morphology: Coarse bluish-green blades; clasping claw-like auricles; sharp, white creeping rhizomes capable of piercing roots..
- Root Architecture: Anchored by a creeping stolons, making manual pulling ineffective unless the entire root crown is extracted.
- Growth Period: Active during perennial cycles, flourishing when lawn turf is stressed or cut too short.
Eradication Protocol & Selective Herbicide Selection
To eradicate Quackgrass while preserving your lawn turfgrass, apply Non-selective Glyphosate spot treatment (few selective options exist in cool turf) during Spring or early fall when quackgrass is 6–8 inches tall and actively growing.. Ensure that the active ingredients match your host turfgrass tolerances:
- Temperature Safety Band: Apply when ambient air temperatures range between 65°F and 85°F. Never apply volatile ester herbicides in temperatures exceeding 85°F to prevent herbicide vapor drift and leaf burn.
- Adjuvant / Surfactant: For waxy or hairy weed foliage, mix with a methylated seed oil (MSO) or non-ionic surfactant according to EPA label instructions to enhance chemical cuticle penetration.
- Mowing Holdback: Do not mow the lawn 2 days prior to spraying or 2 days after application to maximize foliar surface area for chemical absorption.
Frequently Asked Questions About Quackgrass
01 How do I kill Quackgrass without harming my lawn?
Use a selective herbicide labeled for your specific turfgrass species containing Non-selective Glyphosate spot treatment (few selective options exist in cool turf). Spray when Quackgrass is actively growing during spring or early fall when quackgrass is 6–8 inches tall and actively growing.. Always check your host grass in our weed triage tool before application.
02 Why does pulling Quackgrass by hand often fail?
Quackgrass anchors via a creeping stolons. Hand-pulling often breaks the crown or leaves underground root fragments, rhizomes, or nutlets behind, which triggers rapid regrowth. Systemic selective herbicides translocate down through the vascular tissue to destroy the entire root structure.
03 What class of weed is Quackgrass?
Quackgrass is classified botanically as a Grassy weed with a Perennial life cycle.
04 When is the best time of year to treat Quackgrass?
The optimal eradication window is Spring or early fall when quackgrass is 6–8 inches tall and actively growing.. Applying when temperatures are between 60°F and 85°F ensures maximum chemical absorption and prevents foliar heat stress to your desirable lawn.