Invasive Species: Elymus repens, Quackgrass
Quackgrass is an invasive perennial, cool-season, rhizomatous grass. The stems are green to whitish, erect to decumbent and can grow to 3 ft (0.9 m) tall. The leaves are 6-15.7 in. (15-40 cm) long and usually have a pair of prominent auricles at the base. Flowering occurs in May to September. The flower spikes are 3.9-11.8 in. (10-30 cm) long and have 3-8 florets per spikelet. Seeds are elliptical, pale yellow to brown. Each stem can produce up to 400 seeds, but 20 to 40 seeds are common. It also reproduces through rhizomes. Quackgrass is native to Europe and occurs in pastures, gardens, roadsides, and other disturbed open areas.
What are invasive species and why should we be concerned about them?
Taxonomy: Scientific and Common Names for This Species
Cyperales > Poaceae > Elymus repens (L.) Gould
Elymus repens – USDA PLANTS Profile
Distribution Maps
Quackgrass – The reported distribution of this invasive species across the United States (Source: Invasive Plant Atlas of the United States)
Up-to-the-minute distribution maps and why they are important
Reporting This Invasive Species
What is the best way and place to report the occurrence of an invasive species?
How to report an invasive species sighting to EDDMapS – Early Detection & Distribution Mapping System
EDDMapS – Report an invasive species to EDDMapS.
Cooperative Extension Offices – Find your local Cooperative Extension office on this map provided by USDA.
How to Identify
This invasive species can be identified by looking for the characteristics described in the paragraphs that follow.
Grass
Quackgrass is an invasive perennial, cool-season, rhizomatous grass. The stems are green to whitish, erect to decumbent and can grow to 3 ft (0.9 m) tall.
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| Steve Dewey, Utah State University, bugwood.org | Robert Videki, Doronicum Kft., bugwood.org |
Foliage
The leaves are 6-15.7 in. (15-40 cm) long and usually have a pair of prominent auricles at the base.
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| Ohio State Weed lab Archive, Ohio State University, bugwood.org | Ohio State Weed lab Archive, Ohio State University, bugwood.org |
Flower
Flowering occurs in May to September. The flower spikes are 3.9-11.8 in. (10-30 cm) long and have 3-8 florets per spikelet.
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| Robert Videki, Doronicum Kft.,a href=”http://www.bugwood.org/”>bugwood.org | Steve Dewey, Utah State University,a href=”http://www.bugwood.org/”>bugwood.org |
Fruit
Seeds are elliptical, pale yellow to brown. Each stem can produce up to 400 seeds, but 20 to 40 is common. It also reproduces through rhizomes.
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| Julia Scher, USDA APHIS PPQ, bugwood.org | Steve Dewey, Utah State University, bugwood.org |
Native Species That Can Resemble Quackgrass
– Images at invasive.org
| bugwood.org | bugwood.org |
– Images at invasive.org
| bugwood.org | bugwood.org |
Additional Images for Quackgrass
Quackgrass – Images at Invasive.org
Additional Information, Biology, Control and Management Resources
Control and management recommendations vary according to individual circumstances. Location, habitat, weather, and a variety of other conditions are factors that help determine the best treatment choice. To find the safest and most effective treatment for your situation, consult your state’s land-grant institution. If you will use chemicals as part of the control process, always refer to the product label.
United States Land-Grant University System – Find your land-grant university’s college of agriculture, Cooperative Extension office, or other related partner on this map provided by USDA.
Element Stewardship Abstract – The Nature Conservancy
Federal Noxious Weed Disseminules of the U.S. – USDA-APHIS
Weed of the Week – USDA Forest Service