Centipede grass serves as a popular lawn turf in warm, humid climates of the Gulf Coast. The pale green grass spreads by above-ground stems called stolens. Stoloniferous turf competes well with weeds, but it is not immune to annual grass and perennial weed invasions. Typically, you apply pre-emergence herbicides to annual grass weeds when dogwoods are in bloom. Post-emergent herbicides work best when applied to perennial broadleaf weeds three weeks after green-up, according to North Carolina State University Cooperative Extension’s Centipede Grass Lawn Maintenance Calendar.
Crabgrass develops in under-fertilized and frequently mowed lawns. The University Of Florida Institute of Food and Agriculture Sciences' Crabgrass Biology and Management in Turf page says most crabgrass species grow as annual grass weeds, yet blanket crabgrass and India crabgrass grow as short-lived perennials. Crabgrass reproduces by seed. The identification characteristics vary by species, but most types of crabgrass possess a tufted or prostrate growth habit and broad leaves that conspicuously stand out from centipede grass.
Goosegrass grows in compacted soil and lawns with low fertility. The summer annual reproduces by seed and germinates two to three weeks after crabgrass. Goosegrass also looks like crabgrass, but the seed heads are thicker and the leaves are a darker shade of green than crabgrass, according to the University of Tennessee Extension’s goosegrass profile. The extensive root system and rosette-shaped base make the weed difficult to pull.
Prostrate knotweed invades compacted soil and spots worn thin by foot traffic. The annual weed reproduces from seed that germinates in spring. The North Carolina State University TurfFiles page says prostrate knotweed seedlings are frequently mistaken for grass, but prostrate knotweed’s wiry stems radiate from a central tap root and form a low growing mat of blue-green leaves and white flowers.
Pennywort, also known as dollarweed, takes root in wet sites. The perennial weed reproduces via seed, tubers and above-ground stems called rhizomes. The central petiole (leaf stalk) and the scalloped leaf make pennywort look like a small lily-pad, according to the Georgia Center for Urban Agriculture. The weed occasionally produces elongated spikes near the top of the stalk.