Time of bloom: July to September.
Seed-time: August to October.
Range: Throughout the world.
Habitat: Cultivated ground, waste places.
The seeds of this grass must be very long-lived, for, though it is never sown, let the ground be cultivated, and as a general thing Crab-grass will be there. In the Southern States this is regarded as a good thing, for the spontaneous growth of the grass in grain fields after harvest often yields a heavy crop of nutritious hay and good pasturage after that. It is in gardens, lawns, and cultivated ground that the plant makes itself a plague, particularly in a moist season. (Fig. 5.)
Culms one to four feet long, decumbent or creeping at base, and putting forth roots wherever the joints are in touch with moist soil. Sheaths and basal part of the blades rough and more or less hairy, the blades three to six inches long and a quarter to a half-inch wide. Spikes usually three to six in number but occasionally as many as ten, two to five inches long, generally purplish or reddish brown, arranged in a whorl at the end of the stalk like the fingers of a hand. Spikelets in pairs, one sessile, the other having a minute pedicel. The seeds are very nutritious, and in Germany and Poland they are used for a table viand, cooked in milk, like sago.
Fig. 5. - Crab-grass (Digitaria sanguinalis). X 1/4.
Nothing but careful hand labor will clean Crab-grass out of a garden or cultivated field; and it needs to be cast into a fire or a compost heap, for an uprooted stem left on the ground promptly takes root again. In lawns the grass must be hand-pulled, for pieces scattered by lawn-mowers are likely to take root and increase the pest. But if the plant is not allowed to develop seed, two or three seasons of careful weeding should clean it from the soil.