Large crabgrass

Encyclopedia Article

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 sheath.  Smooth crabgrass is similar, but sheaths and blades 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 blade and sheath.

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

Miscellaneous:  Native to Europe. It is believed to be one of the first cultivated grains, and was brought to 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 are wider than those of the foxtails and usually light green in color.

 


Crabgrass has a large membranous ligule.


In turf settings crabgrass assumes a prostrate growth habit that is tolerant of mowing.  

 


Crabgrass inflorescence has 4 to 6 finger-like branches. The genus name, Digitaria, is based on this trait


Mature infestation of large crabgrass with distinct seedheads.

 

Category: 
Weeds
Tags: 
large crabgrass
weed identification
Authors: 

Bob Hartzler

Meaghan Anderson Field Agronomist in Central Iowa

Meaghan Anderson is a field agronomist in central Iowa and an extension field specialist at Iowa State University Extension and Outreach. Educational programming is available for farmers, agribusinesses, pesticide applicators, certified crop advisors, and other individuals interested in...