Tropical Crabgrass is a summer annual grassy weed that is also known as Asian Crabgrass or by its scientific name, Digitaria bicornis. These types of lawn weeds often require a professional application of a select crabgrass killer.
Tropical Crabgrass can be identified as a summer annual grassy weed, bending and rooting at the nodes. Its blades are usually measure over 2 inches long, and it has a visible, membranous ligule at the base of its leaf blades. Tropical Crabgrass produces seeds during mid-summer until the first frost. The seeds of this problematic lawn weed lie dormant over the winter and germinate the follow spring. Tropical Crabgrass differs from Large and Southern Crabgrass in that its seed head branches all join the stem at the same point.
Preferring open, disturbed habitats, this grassy weed frequently competes with other types of desirable lawn grasses. In the United States, Tropical Crabgrass can be found in the southeastern and Gulf Coast states. These grassy weeds are also summer annuals, meaning they begin to grow (germinate) in the spring, mature in the summer and then produce seeds and die by the fall or first hard frost—an entire life cycle completed within 12 months.
Tropical Crabgrass often creates problems during weed control as it interferes with other desirable types of grass in your lawn. Because of the rapid growth habit and reproduction speed this grassy weed possesses, cultural weed control methods—such as hand-pulling lawn weeds or proper watering and mowing—are largely ineffective. For effective weed removal, professionally selected and applied weed control treatments are your best bet for eradication.