Common Crabgrass

<em>Digitaria ciliaris</em>, commonly known as common crabgrass or southern crabgrass, is an annual grass in the family Poaceae. It has a near-cosmopolitan distribution, occurring across tropical, subtropical, and warm temperate regions on multiple continents. This species typically colonizes disturbed habitats including lawns, gardens, roadsides, cultivated fields, and waste ground, making it one of the most widespread grass weeds in the world. Common crabgrass spreads rapidly via its sprawling, branching stems that root at the nodes when they contact moist soil. It produces slender, finger-like racemes bearing small, paired spikelets. The species thrives in warm weather and full sun, declining with the onset of cooler autumn temperatures. While it is considered a troublesome weed in many agricultural and horticultural contexts, it also provides ground cover and food for various seed-eating birds. Biological traits of this species remain poorly documented in the scientific literature.