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Integrated Crop Management
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Large crabgrass

Large crabgrass - Digitaria sanguinalis (L.) Scop

Family: Poaceae
Life cycle: Annual
Native status: Introduced
Habitat: Turf, crop fields

General description: Prostrate or decumbent growth habit, adventitious rooting at nodes of stems. Long, membranous ligule, stiff hairs on the leaf blade, and a sheath. Smooth crabgrass is similar, but sheaths and blades are much less pubescent. Seedhead consists of 3-5 spikes arranged in a ‘finger-like’ arrangement. Crabgrass is lighter green than turf species, so it is very obvious in lawns.

Key ID traits: Membranous ligule, stiff hairs on the blade, and sheath.

Similar species: Smooth crabgrass generally is smaller and lacks hairs on the stem and sheath.

Miscellaneous: Native to Europe. It is believed to be one of the first cultivated grains, and was brought to the US for use as a forage species. Genus name refers to ‘finger-like’ inflorescence. Crabgrass is a bigger problem in ag fields in the southern U.S. than in the Cornbelt due to warmer spring temperatures in the south.

Leaves of large crabgrass seedlings
Leaves of large crabgrass seedlings are wider than those of the foxtails and usually light green in color.

 

large membranous ligule
Crabgrass has a large membranous ligule.
turf crabgrass
In turf settings crabgrass assumes a prostrate growth habit that is tolerant of mowing.  

 

crabgrass inflorescence branches
Crabgrass inflorescence has 4 to 6 finger-like branches. The genus name, Digitaria, is based on this trait
infestation of large crabgrass
Mature infestation of large crabgrass with distinct seedheads.

 

Authored by:
Bob Hartzler
Bob Hartzler
  • Retired Weed Scientist and Professor of Agronomy
Dr. Bob Hartzler is a former professor of agronomy and a former extension weed specialist with a Ph.D. in Crop Physiology from Iowa State University. He conducted research on weed biology and how it impacts the efficacy of weed management programs in corn and soybean. Dr. Hartzler also taught undergraduate classes in weed science and weed identification.
Meaghan Anderson
Meaghan Anderson
  • Field Agronomist in Central Iowa
Meaghan Anderson is a field agronomist serving nine counties in central Iowa and an extension specialist with Iowa State University Extension and Outreach. Areas of expertise include weed management, weed biology, cover crops, corn and soybean management, and integrated pest management.

Meaghan holds a bachelor's degree in agronomy and a master's degree in crop production and physiology (focus: weed science) from Iowa State University.
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