Flower heads with several fingerlike spikes rise from narrow stems. Crabgrass thrives in lawns mowed shorter than 2 in., underfed lawns and those watered frequently and lightly. Thick, deeply irrigated turf is the best control. Dig crabgrass before it seeds. Dandelion is a broadleaf perennial recognized by bright-yellow flowers and a large, flat rosette of leaves rising from a long, fleshy taproot.
Dandelions favor thin turf.
Pull or dig out young plants before they go to seed. Then cut any regrowth from leftover root pieces. You can also spot-treat weeds with a selective broadleaf weed killer. White clover is a broadleaf perennial that used to be included in grass seed mixes. The plant spreads by creeping stems and thrives in sparse, undernourished turf with excessive moisture.