What hardiness zones is Elymus repens suitable for?

Elymus repens is suitable for USDA hardiness zones 3, 4, 5, 6, 7, 8, 9.

What are the sun requirements for Elymus repens?

Elymus repens requires Full Sun.

How much water does Elymus repens need?

Elymus repens has Medium water needs.

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Wild Grasses

Elymus repens

quackgrass

Poaceae

Europe, western and central Asia; naturalized across most of the United States and all Canadian provinces

At a Glance

TypeGrass

HabitSpreading

FoliageDeciduous

Height12-48 inches (30-120 cm)

WidthIndefinite spread via rhizomes; 3-10 feet per year

Maturity2 years

Growing Zones

USDA Hardiness Zones

3 - 9

Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9

These zones indicate the coldest temperatures this plant can typically survive.

What's my zone? →

Frost Tolerancehardy

Key Features

Drought Tolerant

Maintenancehigh

Overview

Elymus repens is a cool-season perennial grass in the family Poaceae with an extensive underground rhizome system that allows aggressive colony formation. Plants produce erect stems typically reaching 12–48 inches (30–120 cm) tall with flat linear leaves that are blue-green to gray-green in color and measure 4–10 inches (10–25 cm) long and 0.08–0.4 inch (2–10 mm) wide. The upper leaf blade surface is scabrous (rough to the touch from minute silica hairs) while the lower surface is smooth; prominent parallel veins run the length of the blade. The underground rhizome system extends horizontally 3–10 feet (0.9–3 m) per year at depths of 2–6 inches (5–15 cm), with adventitious shoots emerging every 2–6 inches (5–15 cm) along the rhizomes. Rhizomes are white, segmented, and sharply pointed at the growing tips — the pointed tips can pierce potato tubers and other soft root vegetables during rhizome spread. Rhizome fragments as small as 0.5 inch (1.25 cm) with a single node regenerate into new plants, making fragmentation by cultivation equipment the principal mechanism by which infestations spread within agricultural fields. Inflorescence is a terminal spike 2–8 inches (5–20 cm) long with spikelets arranged alternately along the rachis (edgewise on opposite sides of the stem). Each spikelet contains 3–7 florets and may have short awns or be awnless. Listed as a noxious weed in several U.S. states. Not known to be toxic to pets or humans — the species can be grazed by livestock, though coarse texture limits palatability.

Native Range

Elymus repens is native to Europe, western and central Asia, extending from the Mediterranean region through temperate areas of the continent. The species has been widely introduced to North America and is naturalized across most of the United States and all Canadian provinces. It occurs in cultivated fields, pastures, gardens, roadsides, and disturbed ground from sea level to moderate elevations.

Suggested Uses

Used primarily for erosion control on disturbed slopes and road-cut embankments where the aggressive rhizome spread rate and deep root penetration stabilize bare soil within 1–2 growing seasons after sowing. The species is unsuitable for ornamental landscape plantings, lawn areas, vegetable gardens, and perennial borders because of the indefinite rhizome spread and the rhizome fragmentation hazard from cultivation. In pasture and hay production, the species is considered a contaminant rather than a desirable forage, with coarse texture reducing palatability and productivity compared with Dactylis glomerata or Lolium perenne. In wildlife habitat restoration in regions where the species is native (Europe, western Asia), the dense rhizomatous mat carries ground-cover habitat for small mammals and ground-nesting birds. Rhizomes have been used in traditional European herbal preparations.

How to Identify

Habit is erect stems 12–48 inches (30–120 cm) tall arising from extensive spreading rhizomatous root systems, with colony footprint extending indefinitely via rhizome growth. Leaves are flat, linear, 4–10 inches (10–25 cm) long, 0.08–0.4 inch (2–10 mm) wide, blue-green to gray-green, with scabrous (rough) upper surfaces and smooth lower surfaces bearing prominent parallel veins. The underground rhizome system is the primary identification character — white segmented rhizomes with pointed growing tips run horizontally 2–6 inches (5–15 cm) below the soil surface and send up new shoots at each node. Inflorescence is a terminal spike 2–8 inches (5–20 cm) long with spikelets arranged alternately and edgewise along the rachis. Compared with Agropyron cristatum (crested wheatgrass), spikelets run edgewise along the rachis rather than flattened against one side and the species is strongly rhizomatous rather than bunch-forming; compared with Hordeum species (wild barley), spikelets lack the long three-part awns and are arranged singly rather than in triplets at each rachis node; compared with Lolium perenne (perennial ryegrass), rhizomes are present and extensive rather than absent entirely with the ryegrass confined to a basal tuft.

Appearance

Size & Dimensions

Height1' - 4'

Width/Spread3' - 10'

Reaches mature size in approximately 2 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Spring Summer

Terminal spikes 2–8 inches (5–20 cm) long with edgewise-alternating spikelets appear from May through July. Wind-pollinated flowering occurs over 2–3 weeks per spike. Seeds mature 3–5 weeks after pollination in July–August. Seed dispersal is limited (0.5–2 feet / 15–60 cm from the parent plant) but rhizome spread is the principal mechanism of colony expansion rather than seed dispersal, with rhizomes extending 3–10 feet (0.9–3 m) per year under favorable conditions.

Detailed Descriptions

Flower Description

Green to pale yellow; terminal spike 2-8 inches long with edgewise-alternating spikelets; wind-pollinated

Foliage Description

Blue-green to gray-green; flat linear 4-10 inches long by 0.08-0.4 inch wide; scabrous (rough) upper surface, smooth lower surface, prominent parallel veins

Growing Conditions

Sun Requirements

Full Sun Partial Shade

Requires 4-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)

357912

Soil Types

loam clay sand silt

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Management of established infestations is difficult because the rhizome system stores large carbohydrate reserves that fund regrowth after defoliation. Cultivation fragments rhizomes into 0.5-inch (1.25 cm) segments that each regenerate, which makes tillage counterproductive unless followed by repeated deep cultivation every 2–3 weeks for a full growing season to exhaust root reserves through repeated regrowth cycles. Smothering under black plastic or heavy cardboard for 12–18 months kills rhizomes in the covered area through light exclusion. Repeated cutting or mowing at the 4-leaf stage before flowering for 3–4 consecutive growing seasons gradually depletes rhizome carbohydrate reserves. Hand-pulling removes above-ground stems but leaves the rhizome system intact; new shoots emerge within 2–4 weeks of surface removal. In small garden infestations, systematic removal of rhizomes by careful excavation of the entire root mass with a garden fork — not a spade, which slices rhizomes — gives more thorough removal than chemical or chopping methods. The species grows on a wide range of soil types and pH values from 6.0 to 8.0 but runs most vigorously on moist well-drained agricultural soils where rhizome spread rates reach 10 feet per year.

Pruning

No horticultural pruning applies; management is through removal of rhizomes rather than top growth. Cutting above-ground stems before seed set reduces seed contribution to the soil seed bank but does not impact rhizome-based reproduction — rhizomes continue spreading regardless of top-growth removal. Systematic excavation of rhizomes with a garden fork in garden settings, or repeated 2–3 week cultivation cycles through a full growing season in field settings, depletes rhizome reserves more reliably than cutting alone.

Maintenance Level

high

⚠️ Toxicity Warning

Non-toxic