How do I tell the difference between crabgrass and quackgrass?

Question:

Answer:

Crabgrass (Digitaria spp.) and quackgrass (Elymus repens) are two weedy grasses that stand out in traditional lawns as the leaves are much coarser than the Kentucky bluegrass, perennial ryegrass, and fescues that are typically planted in the cool-season lawns common in Iowa.

While these two weeds feel familiar to many gardeners, they are often confused. Proper identification is beneficial because they are managed in different ways.

Crabgrass control: How to Control Crabgrass

Quackgras control: How to Manage Perennial Grassy Weeds in the Garden and Lawn

Comparison of crabgrass and quackgrass
Crabgrass	Quackgrass
annual (germinates from seed every year)	perennial (comes back from the same root system each year)
warm-season (appears later in the growing season)	cool-season (typically noticed early in the growing season)
prostrate (low) growth habit, especially when mown	more upright growth habit, espeically if unmown
medium to light green in color	dark green in color
no rhizomes, produces tillers that can root at nodes	abundant, long, thin, white rhizomes are found underground
membranous ligule near the base of the leaf blade	clasping auricles near the base of the leaf blade
flower/seedhead is branched into 3 to 5 finger like projections	flower/seedhead is slender and upright

large crab grass — crabgrass showing its prostrate growth habit and tiller extending from the main growing point

quack grass with rhizomes — quackgrass showing the white underground rhizomes

crabgrass ligule — membranous ligule of crabgrass

quackgrass auricles — the clasping auricles of quackgrass

crabgrass seedheads — crabgrass has branched seedheads

quackgrass seed heads — quackgrass has slender seedheads

Photos courtesy of Iowa State University Integrated Crop Management Team

Last updated on

July 24, 2025