Purslane is a prolific seed producer and seeds may lie dormant in soil for many years before germinating. Clover is a very common weed in nearly all turfed areas. Although some homeowners do not find clover objectionable, its creeping growth habit can overtake turf and form large dark-green patches. Clover leaves are composed of three leaflets, each with a small white mark in the center. Stems grow above ground and root at nodes.
Wild violets are persistent perennial weeds that are difficult to control in turf.
This species is an upright grower that spreads by means of thick underground stems. Leaves are heart-shaped and margins are serrated. The leaf surface is shiny owing to a thick waxy covering. Flower petals are purple, and the center of the flower is white or yellow. Two types of hawkweed grow in Pennsylvania, yellow and orange.