Crabgrass is a warm-season annual grass that thrives in hot weather and disturbed soil, rapidly colonizing open spaces. While often viewed as a nuisance, crabgrass serves as a food source for various organisms, including grazing animals, insects, and historically, humans.
Herbivores and Livestock
Crabgrass provides palatable and nutritious forage for many grazing animals. It was introduced to the United States in 1849 specifically as a forage crop for livestock like cattle, sheep, hogs, and horses. Today, it remains a high-quality forage in livestock operations, especially during summer when other cool-season grasses decline.
Wild herbivores also consume crabgrass. Rabbits eat crabgrass for fiber. Deer, though not primarily grass eaters, may graze on it when other food sources are scarce.
Birds and Other Seed Eaters
Crabgrass’s prolific seed production makes it a food source for many bird species. A single plant can produce up to 150,000 seeds. Wild birds, such as sparrows and finches, consume these seeds as a valuable food source. This consumption also contributes to crabgrass dispersal, as birds spread the seeds across different areas.
Insects That Feed on Crabgrass
Various insects feed on crabgrass, though their activity is generally detrimental to lawn health. Grubs, the larval stage of beetles like Japanese beetles and June bugs, feed on crabgrass roots. This root damage can cause patches of lawn to thin, turn brown, and become easy to pull up.
Other insect pests target the foliage and stems. Chinch bugs pierce grass blades and suck out plant juices, leading to irregular patches of yellowing and browning turf, especially in hot, dry conditions. Cranberry girdlers, a type of sod webworm, damage grass by feeding on roots and crowns, causing patches to brown and die. Grasshoppers also consume crabgrass and can cause significant damage.
Beyond Wildlife: Human Consumption
Crabgrass has a surprising history as a human food source across various cultures. Stone Age communities in Switzerland cultivated it, and it was an important food crop in China as early as 2700 B.C. It remains a traditional staple grain in parts of India and Africa.
Crabgrass seeds can be ground into flour, used as couscous, or prepared as a grain in dishes like porridge. In some regions, the grain is also fermented for beer making. Despite its weed reputation in many Western countries, crabgrass was purposely planted as a food source in the United States until the 1940s, valued for its nutritional content and rapid growth.