WSU Extension

Hortsense

Weeds : Ryegrass, annual (Italian ryegrass) : Lolium perenne ssp. multiflorum
(revision date: 4/7/2021)

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

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

Biology
Annual ryegrass is upright, growing in clumps often reaching four feet tall. The flat leaf blades are shiny and about 1/8 to 1/4 inch wide. The veins are prominent, making the blades appear ridged. The ligule, occurring at the point where the leaf blade joins the leaf sheath, is short and membranous. Claw-like appendages (auricles) often clasp the stem near the base of the leaf blade. Seeds are borne in spikelets on long (to twelve inches), flat spikes at the tops of the stems. A related species, perennial ryegrass (L. perenne ssp. perenne) is commonly used in turf, but annual ryegrass is not recommended for lawn seed mixtures, as it tends to persist and is unattractive in the established lawns.
Habitat
Annual ryegrass may be found on roadsides and is a major weed in cultivated areas. It is sometimes included in pasture and lawn seed mixtures as a cover crop for temporary turf.

Management Options

Non-Chemical Management
  • Maintaining a healthy planting or turf area to provide competition will prevent weed establishment.
  • Cultivation (rototilling or hoeing) will effectively eliminate plants.
  • Hand-pull to eliminate weeds.
  • Careful digging is useful to manage weed populations. However, digging can carry undesirable weed seed to the surface and foster further germination.
Select non-chemical management options as your first choice!

Chemical Management

Read the label for application timing of the products listed. 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
  • oryzalin
  • products containing benefin
  • trifluralin
  • products containing diquat
  • sethoxydim
  • fluazifop
Turf areas
    Bare ground areas
    • glyphosate
    • products containing diquat
    • dichlobenil
    Images
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    Caption: Annual ryegrass
    Photo by: T.W. Miller
    Caption: Annual ryegrass seed heads
    Photo by: T.W. Miller
    Caption: Annual ryegrass auricles
    Photo by: R. Parker
    Caption: Annual ryegrass seedling
    Photo by: J. A. Kropf
    Caption: Ryegrass flowers
    Photo by: T. W. Miller
    Caption: Ryegrass shiny leaves
    Photo by: T. W. Miller
    Caption: Ryegrass spikelets
    Photo by: T. W. Miller