Crabgrass Identification


Crabgrass (digitaria) is an annual grass that thrives in warm weather, particularly in the middle of the summer. Crabgrass is considered to be an invasive weed by many gardeners. In general, gardeners aim to eliminate crabgrass from their lawns. Crabgrass is a genus that is comprised of approximately 300 different grass species, and originates in tropical and temperate regions. It is also known as fonio and finger-grass.


Crabgrass generally has a spreading stem, with leaf blades that are both flat and wide. The leaf blades generally are on the ground and have ascending tips. The spikelets of crabgrass are situated in two different rows on a winged or angled rachis (the primary axis or shaft). Every spikelet consists of two florets, and only one of them is fertile.


Although many people consider crabgrass to be a weed and therefore useless, there are actually various common uses. These uses include production of floor (their seeds can be toasted and then ground up and then used for beer or porridge) and cattle forage (it has various nutrients). In some areas of Africa, crabgrass is a staple crop.


There are many different species of crabgrass. Some well-known varieties of crabgrass include digitaria exilis, digitaria insularis, digitaria ischaemum, digitaria sanguinalis, digitaria filiformis, digitaria ammophilia, digitaria horizontalis and digitaria violascens.

Digitaria sanguinalis

In North America, the most common species of crabgrass is digitaria sanguinalis, which is also known as either smooth crabgrass or hairy crabgrass. This type of grass is often problematic for gardens and lawns. It thrives in lawns with grass that is thin, lightly watered or poorly fertilized or drained. They are annuals, and one plant is able to produce 150,000 seeds seasonally.


For cultivating crabgrass, full sun is preferable. The grass can grow to be between 3 and 12 feet in height. Crabgrass can be grown in the U.S. Department of Agriculture's (USDA) plant hardiness zones of between 3 and 10. The rapid-growing grass prefers soil that is well-drained, sandy and loamy.


Although crabgrass is occasionally cultivated (because of its various different uses, such as flour production), it is rare, due to the fact that the majority of gardeners aim to eliminate this invasive weed. Crabgrass control is a common issue many gardeners face. This can be done with the use of pre-emergent herbicides. Crabgrass can be stopped from growing in the first place by stopping either seed germination or formation.

Keywords: crabgrass, digitaria, fonio

About this Author

Isabel Prontes is a freelance writer and traveler residing in Manhattan, NY. She has traveled to five continents and counting. Her work has appeared on a number of websites, such as Travels, and "Happy Living Magazine." Prontes has a professional background in public relations; she received a bachelor's degree in communication studies from Pace University.