Quackgrass

Quackgrass (Elymus repens) is a cool-season perennial grass with flat, rough-textured bluish-green blades and a coarse, upright habit that stands out from finer lawn grasses. Its most distinctive diagnostic features are a pair of long, narrow, claw-like clasping auricles that wrap completely around the stem at the collar where blade meets sheath, combined with a short membranous ligule. The seedhead is a slender, narrow spike resembling that of wheat or ryegrass, with spikelets set flatwise against the stem. The defining trait, however, is belowground: quackgrass produces long, white-to-yellowish, sharp-pointed, aggressively spreading rhizomes that can extend many feet, allowing it to be told apart from clumping grasses and from tall fescue, which lacks such vigorous rhizomes.

In turf, quackgrass forms coarse, fast-growing, bluish-green patches that grow taller and rougher than the surrounding lawn, producing an uneven, clumpy texture and color contrast that ruins uniformity. Its vigorous rhizomes let patches expand steadily and outcompete desirable grasses, and because no selective herbicide removes it from established cool-season turf, infested areas remain conspicuously weedy and progressively degrade the stand.

Quackgrass is a cool-season perennial that spreads both by seed and, far more aggressively, by an extensive system of tough, sharp-tipped rhizomes that can grow several feet long and pierce through soil and even other plant roots. New shoots arise all along the rhizomes, so a single plant rapidly forms an expanding patch. It grows most actively in the cool conditions of spring and fall and tends to slow or go dormant in hot summer weather; the durable rhizome system makes it one of the most persistent and difficult perennial grasses to eliminate.

It is favored by cool-season climates and establishes readily in disturbed, neglected, newly seeded, or thin turf, as well as field edges and renovation sites. Because it spreads by rhizomes, any soil disturbance that fragments and redistributes those rhizomes (such as tillage or careless cultivation) spreads the infestation. Open or thin turf in spring and fall gives both its seedlings and rhizome shoots the room to invade and expand outward into surrounding grass.