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Quackgrass

Elytrigia repens

Updated Sep 15, 2023

Make a Positive Identification

Quackgrass is an aggressive, perennial (lives many years) grass.
It grows up to 4 feet tall from seeds and creeping roots (rhizomes).

Species: Quackgrass

Rasbak, CC BY-SA 3.0, via Wikimedia Commons

Quackgrass grows 1–4 feet tall. It thrives in disturbed areas. It is often found in croplands, moist meadows, lawn drainage ditches, roadsides, and along creeks and rivers.

Species: Quackgrass

Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, via Wikimedia Commons.

Stems grow horizontal from the base of the plant then bend upwards. Leaves are flat and ¼–½ inch wide, 4–12 inches long. The leaves get narrow 1–2 inches behind the tip.

Species: Quackgrass

White box highlighting auricle and rolled, elongated leaf blade

Ohio State Weed Lab , The Ohio State University, Bugwood.org

Quackgrass leaf blades have two clasping structures called auricles. They grow from where the leaf blade connects to the stem (leaf sheath). The auricles are narrow, often claw-like. Their color is pale green to pale purple as highlighted in the white box in the photo.

Species: Quackgrass

Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, via Wikimedia Commons

Flowers grow on a flattened spike that is 2-10 inches long. Flowers appear from late spring through summer and produce a few dozen seeds per plant. Seeds are viable for 1–6 years.

Species: Quackgrass

Doug Doohan, Ohio State University/ OARDC, Bugwood.org

Seedlings look like mature plants, but auricles may not be developed. Young plants grow rhizomes when 6 to 8 above-ground stems are present.

Species: Quackgrass

Quackgrass roots and stems against blue background

Steve Dewey, Utah State University, Bugwood.org

Once seedlings establish, quackgrass rhizomes (root system) spread to increase the size of the patch.

LOOK-ALIKES: RYEGRASSES AND OTHER ELYMUS SPECIES

Species: Annual ryegrass & perennial ryegrass

Joseph M. DiTomaso, University of California - Davis, Bugwood.org

Annual ryegrass and perennial ryegrass (Lolium multiflorum and Lolium perenne) are grasses used in pastures and found in lawns.
Their leaves and flowers are similar to quackgrass. However, they do not grow rhizomes.
For example, the perennial ryegrass in the photo could be removed as a clump. It would not grow back.

Species: Native Species

Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, via Wikimedia Commons

Native Elymus grass species, such as blue wildrye (Elymus glaucus) are planted in landscapes and revegetation projects.
Telling native Elymus species from quackgrass is difficult. Use flowers to ensure correct identification.
Your local Extension Specialist in Oregon and other states can identify grasses for you.

Different risks or methods

Native grasses are desired species and don’t usually require management.

Quackgrass Benefits

Quackgrass is forage for grazing animals.
It mixes into lawns when mowed.

Quackgrass Risks

Quackgrass forms dense stands that displace desired vegetation.
It significantly reduces crop yields and hosts cereal crop diseases.
It grows in urban landscapes and lawns and is difficult to control.

Risk Card

Does it cause harm?

Adults & Children

None

Property

High

Pets

None

Annoyance

High

Environment

Some

Action Recommended

TAKE ACTION?

If you have quackgrass on your property, determine whether you can tolerate it in lawns, landscapes, and orchard areas. If not, take action to control it.

Do I need to take action?
Yes. Remove individual plants and small patches in areas where you can’t tolerate it. Established patches require several years to control.

What if I do nothing?
Quackgrass forms dense stands and is difficult to control. The longer you wait to act, the more difficult it will be to control it.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.

Solutions for Quackgrass

Early Detection & Rapid Response

Watch for quackgrass on property you manage. Remove it before it becomes a bigger problem in areas where you can’t tolerate it.

Physical Removal of Plants & Non-chemical Methods

Young, single quackgrass plants and small patches can be removed from softened, moist soil with hand tools. Remove all of the rhizomes fragments. Any remaining fragments will sprout and grow new plants.
Mowing, burning, or grazing quackgrass will not suppress its spread.
Cultivation (breaking up the soil surface with a hoe or machine) provides benefits when used with other control activities. If used alone, cultivation will spread quackgrass.
Quackgrass does not tolerate shade.

Herbicides (Weed Killers)

Herbicides effectively control quackgrass when used according to the label instructions.
Combine these non-chemical methods with herbicide treatments. Re-treating is necessary for eradication.

Monitoring & Follow Up

Look for new quackgrass regrowth and seedlings on your property each year.
After you remove it, new plants will grow in the same spot unless you take steps to prevent them.

Method	Does it work?	Is it safe?	Recommendation
A Physically Remove Plants	Effective	Low risk	Recommended
B Mowing, Disking & Tarping	Somewhat effective	Low risk	Recommended
C Glyphosate, Imazapyr & Grass-Selective Herbicides	Effective	Moderate risk	Use if Necessary
D If Using Herbicides, Protect Yourself & Minimize Risks
E Prevent Quackgrass

Physically Remove Plants

Non-Chemical Method

Steve Dewey, Utah State University, Bugwood.org

Physically Remove Plants

Recommended

Dig out small patches. All rhizome fragments must be removed. This is extremely difficult if you are managing an established stand.

Does it work?	Effective Use preventive measures for best results.
How much effort?	High effort Quackgrass requires several years of monitoring and effort to control.
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Juta.lopp, CC BY-SA 3.0, via Wikimedia Commons

Photo shows quackgrass root mass and rhizomes
Dig out young, individual plants and small patches, and make sure to remove the root mass and all the rhizomes.
Quackgrass spreads primarily with rhizomes. New plants establish from seed.
You must remove the rhizomes to get rid of quackgrass plants.

Soil Disturbance and Erosion

Minimize soil disturbance as much as possible.
Regrade the soil after digging quackgrass roots. Apply mulch (when appropriate).
Take steps to prevent erosion as needed.
Replant the area to shade quackgrass regrowth and seedlings.

Mowing, Disking & Tarping

Non-Chemical Method

Andrei310, iStock

Mowing, Disking & Tarping

Recommended

Mowing, tilling, and smothering methods help manage quackgrass, but additional effort is required to get rid of it.

Does it work?	Somewhat effective Use preventive measures for best results.
How much effort?	High effort
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Mowing will not get rid of quackgrass, but keeps it in an acceptable condition for low-maintenance lawns and fields.
Quackgrass is sensitive to tillage such as disking or plowing, and these actions require additional control effort.

Ohio State Weed Lab , The Ohio State University, Bugwood.org

Mowing

Mowing alone does not control quackgrass.
Mowed quackgrass blends into lawn areas. It is acceptable ground cover for low-maintenance lawns and fields.
Combine mowing with other control activities to eliminate quackgrass.

Tractor with disk attachment cultivating field

freeteo, iStock

Disking

Using a tractor disk attachment loosens soil and breaks up quackgrass rhizomes, but will not control quackgrass on its own.
Combine disking with other control activities to eliminate quackgrass.
Fragmented rhizomes will generate new plants. Clean equipment to avoid spreading rhizome fragments.

Master Gardener Volunteer, Oregon State University

Tarping

Small patches of quackgrass can be covered with a light-impenetrable barrier. Thick synthetic tarps, landscape fabric, or geotextile fabric products are examples of materials to use. Weigh them down at the edges. Be sure to extend the tarp well beyond the edges of the infestation. Check periodically to make sure plants are not growing up around the tarp.
This method is only feasible if you can leave the covering in place throughout the growing season. The objective is to deprive the plants of light.
Combine this method with other control activities to eliminate quackgrass.

Glyphosate, Imazapyr & Grass-Selective Herbicides

Chemical Method: Use with caution

Chameleonseye, iStock

Glyphosate, Imazapyr & Grass-Selective Herbicides

Use if Necessary

Herbicide products that contain active ingredients glyphosate or imazapyr, and herbicides that target grasses (grass-selective), are effective treatments for quackgrass when label directions are followed.

Does it work?	Effective Use preventive measures for best results.
How much effort?	Moderate effort Quackgrass requires several years of monitoring and treatment.
What's the risk?	Moderate risk Herbicides come with real risks. ALWAYS read the entire label front to back. Review instructions even for brands you know. Herbicides can run off your site into waterways and may harm wildlife. See How to Keep Pesticides Out of Waterways.
Possible risk of exposure or harm from chemicals	Using herbicides includes some amount of risk. The lowest risk comes with using alternative methods. You may be exposed to an herbicide if you: Get it on your skin Breathe it in Eat or smoke afterward without washing hands Touch or eat plants that are wet with spray (you, pets, or children) Bring it inside on your shoes or clothes Follow directions closely to reduce risk.

Herbicide products that contain active ingredients glyphosate and grass-selective herbicides such as fluazifop effectively control quackgrass when label instructions are followed. Look for these chemical names in the “Active Ingredients” section of product labels.

Photo of herbicide label highlighting active ingredient glyphosate

Weston Miller, Oregon State University

The white box on the example label highlights active ingredient glyphosate. Text on the label states “Kills grass and weeds around flower beds....”
Glyophosate will damage most plants and grasses. Don’t let the spray contact plants you want to keep.

Photo of herbicide label highlighting active ingredients glyphosate and imazapyr

Weston Miller, Oregon State University

The white box on this example product label highlights active ingredients glyphosate and imazapyr. The text on the label states “Kills weeds for up to 1 year.”
Products with imazapyr will kill most grasses and broadleaf plants. Don’t let the spray contact plants you want to keep.

Photo of herbicide label highlighting active ingredient fluazifop

Weston Miller, Oregon State University

Grass-selective herbicides such as fluazifop effectively control quackgrass.
These products don’t injure desired plants when used as directed on the label instructions. They can be used around ground covers, flower beds, and shrubs (bushes), and trees.
The white box on the example label highlights active ingredient fluazifop. The text on the label states “KILLS WEEDY GRASSES WITHOUT INJURING ORNAMENTAL PLANTS.”

Herbicide Application Tips

Premixed products are available in stores.
Killing rhizomes is critical to eliminating quackgrass.
Herbicide products applied to the leaves in spring or fall are effective at controlling spread.
Herbicides applied after flowering are more effective at killing rhizomes.
However, the specific timing and application method depend on the herbicide product. Follow the label instructions for best results.
It takes repeated effort over several years to get rid of a well-established stand of quackgrass.

Herbicide Application Requirements for Aquatic Areas

Herbicides applied over or near a body of water must be registered for aquatic use.
Treating quackgrass near aquatic areas requires specialized skills. This ensures the herbicide is applied effectively. It also protects waterways.
Consider hiring a licensed pesticide applicator to manage this weed in aquatic areas.
Aquatic-use products are rarely sold at plant nurseries or garden centers. They are available through specialty pesticide dealers.
Aquatic formulas of herbicide products that contain active ingredients glyphosate and imazapyr effectively control quackgrass when used according to label directions.
Other aquatic-use herbicide products may be legal in your area. Consult a licensed pesticide applicator or your local university extension agent before purchasing an aquatic herbicide product.

If Using Herbicides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution

SteveOehlenschlager, iStock

Why is it important to read herbicide labels?

They have detailed information on how to use the product correctly and legally.
They contain information on potential hazards of the product.
They provide instructions you should follow for poisonings and spills.
Following label instructions helps to minimize the risks and maximize the benefits.

Key Herbicide Safety Tips

Read the entire label front to back.
Follow the instructions.
Review the instructions even for brands you know.
Only apply the product where the label says it may be applied.
Be precise in your application. More is not better.

The Label is the Law

ALWAYS read the label before using herbicide products. The label is a legal document that provides information on how to safely use the herbicide. This helps avoid harm to human health and the environment. Using an herbicide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

Labels are different for every product and they often change over time.
Use a magnifying glass if needed.
Pay attention to CAUTION, WARNING, and DANGER statements.
Pay attention to the PRECAUTIONARY STATEMENTS.
The law states you must read and follow herbicide instructions.

Protect Yourself
Eye, skin & lung irritants

Wear the right protective gear. This often includes chemical-resistant gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
Mix outdoors or in a well-ventilated area.
Wash hands after mixing or applying, and before eating or smoking.
Take a shower immediately after handling herbicides.
Wash clothes worn while mixing or applying separately from other laundry.

Protect Children & Pets
Children and pets are at risk if they eat or touch the plants before it dries.

Keep them away during and after applying herbicides (read label for how long).
Remove toys and pet dishes from yard before applying.
Don’t track herbicide products into your home on shoes or clothes.

Don’t Spray into Water

It’s illegal to apply herbicides in a stream or slow moving/wetland pool.
You need a product registered for aquatic areas. This includes waterways, ditches, drains, and other places where water collects.

Protect Plants You Want to Keep

Glyphosate and similar herbicide ingredients damage both grass and broadleaf plants.
Minimize spraying of foliage, stems, exposed roots, or the trunks of desirable shrubs or trees to avoid harm.
Follow the label to avoid damaging the roots of trees and shrubs.

Avoid Wet, Windy, or Hot Weather
Use during favorable weather for best results.

Don’t spray when it’s raining or when rain is expected in the next 24 hours.
Wind causes spray to drift that can get on you and desired plants.
Herbicides may be less effective in hot weather if the target plants are moisture-stressed.
Some herbicides can turn into a vapor in hot weather and damage nearby plants.

Storage & Disposal

Store in a secure area away from children.
Don’t put unused herbicide products in the trash.
Never pour down any drain or waterway.
Take unused herbicides to a hazardous waste facility.

Call 1-800-CLEANUP (1-800-253-2687) to find out where to dispose of herbicides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call 503-234-3000, email or visit Metro’s website

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management (Oregon Department of Agriculture).