Crabgrass (Digitaria species) This infamous summer annual
thrives in warm, moist areas. Seeds germinate in early spring in
warmer climates, later in cooler areas. As the plant grows, it
branches out at the base; stems can root where they touch the
soil. In flower beds, pull crabgrass before it sets seed. To
thwart crabgrass in lawns, keep the turf well fertilized and
vigorous, so it will provide tough competition for weeds. Also
water your lawn deeply, but infrequently; this tactic will dry
out crabgrass roots, killing the weeds or at least diminishing
their vigor. Solarization can control crabgrass if high
temperatures are achieved. Use corn gluten as a preemergence
treatment. If chemical control is necessary, in ornamental beds
only, use a postemergence herbicide control that kills grasses.