WSU Extension

Hortsense

Weeds : Quackgrass : Elymus repens (Elytrigia repens, Agropyron repens)
(revision date: 4/7/2021)

Family: Poaceae (Graminae)
Cycle: Perennial
Plant Type: Grass

Use Integrated Pest Management (IPM) for successful weed management.

Biology
Quackgrass is a perennial grass which spreads by both seeds and rhizomes, forming dense clumps if left unchecked. The spreading rhizomes are typically pale yellow in color and sharply pointed at the tips. Uncut plants are one to three feet high. The leaves are narrow and flat with rough upper surfaces. Leaf blades are frequently constricted near the tip, which helps in identifying non-flowering plants. The seed head of flowering plants consists of two rows of spikelets on opposite sides of the spike. The seed head is typically six to ten inches long. SPECIAL INFORMATION: Quackgrass can be difficult to eradicate once established. Repeated cultivation to expose and cut up the rhizomes has been effective in some areas. In Oregon, quackgrass is on the noxious weed quarantine list, which prohibits sale, purchase, and transport of plants, seeds, and plant parts.
Habitat
Quackgrass is common in fields, grasslands, and waste areas on fertile soils. It may invade newly planted lawns, and also may become a problem in home gardens and ornamental plantings.

Management Options

Non-Chemical Management
  • Digging and carefully removing all rhizomes will effectively eliminate single plants and small infestations.
  • However, this is very time consuming and frustrating.
Select non-chemical management options as your first choice!

Chemical Management

Apply according to label directions. Spot treatments with certain post-emergent herbicides will control weedy grasses, but will also kill the turf. Glyphosate products should be applied as spot treatments only! NOTE: Some ingredients listed here are only available in combination. Read the label carefully on combination products to make sure the product is suitable for your specific situation.

Landscape areas
  • glyphosate
  • dichlobenil
  • fluazifop
Turf areas
    Bare ground areas
    • glyphosate
    • dichlobenil
    Images
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    Caption: Quackgrass
    Photo by: D.G. Swan
    Caption: Quackgrass leaves and auricles
    Photo by: D.G. Swan
    Caption: Flowering quackgrass
    Photo by: T.W. Miller
    Caption: Quackgrass rhizomes and shoots
    Photo by: T.W. Miller
    Caption: Quackgrass rhizomes
    Photo by: T.W. Miller
    Caption: Quackgrass seed heads
    Photo by: D.G. Swan