Quackgrass (Agropyron repens (L.) Beauv.)
Quackgrass is a cool-season perennial grass that spreads aggressively by an extensive system of fast-growing rhizomes. It forms dense patches and clumps of upright stems that may reach up to 4 feet tall.
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Leaves and stems are green. Leaves are flat, narrow (0.3–16 mm wide), and range from 1.5 to 12 inches long. Leaves are rolled in the bud and have a small pinch or indentation 1–2 inches from the tip. The upper leaf surface may be smooth or slightly hairy, while the lower surface is hairless.
Leaf sheaths are open around the stem and rounded, sometimes with short hairs near the base of the plant. Ligules are small, membranous, and fringed. Auricles are thin and clasp the stem, often appearing white, green, or reddish — a key identifying feature.
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Quackgrass flowers from mid-spring through late summer. Seedheads are long, narrow spikes (2–8 inches long) made up of many individual spikelets arranged alternately in two rows along the stem. Seeds form in small awns.
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The root system consists of aggressive, creeping rhizomes with sharply pointed tips that allow the plant to penetrate soil and even the roots of neighboring plants, contributing to its invasive nature.
Quick ID Guide
Life Cycle:
• Perennial
• Spreads by rhizomes and seed
Height:
• Up to 4 feet tall
Roots:
• Extensive, fast-growing rhizomes
• Pointed rhizome tips
Leaves:
• Flat and narrow
• 1.5–12 inches long
• Rolled in bud
• Small pinch near tip
• Upper surface smooth or slightly hairy
• Lower surface hairless
• Thin, clasping auricles
Flowers (Mid-Spring–Late Summer):
• Long, narrow spike (2–8 inches)
• Spikelets arranged in two rows
Seeds:
• Produced in small awns
Management Options
Prevention and cultural control strategies should be prioritized whenever possible to limit establishment and spread.
At this time, there are no approved biological control agents available for quackgrass.
Hand pulling or digging is generally not recommended for established infestations, as rhizome fragments can resprout and create new plants. Small, isolated patches may be removed carefully if all rhizome material is extracted. Mowing is typically ineffective because the plant readily regrows from rhizomes.
Aggressive tillage methods, such as moldboard plowing, may suppress quackgrass but are often impractical in shallow or rocky soils. Grazing is usually not effective for long-term control, and caution should be exercised since ergot, a toxic fungus, may occur on quackgrass.
Herbicides can provide effective control when properly applied. For many products, treatment is most effective before shoots exceed 8–12 inches in height. Some herbicides may also be used later in the season to reduce rhizome biomass. Always read and follow herbicide label directions carefully. Contact your local weed and pest district for guidance on product selection and application rates.
