St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae, tribe Panicae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Floratam (coarser, dark green, wide blades, widely adapted in Florida and the Gulf Coast)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10 (and warm parts of 11). Highly sensitive to cold, turning straw-colored (dormant) with the first hard frost below freezing. Poor cold tolerance compared to cool-season grasses.
About This Grass
St. Augustine grass is a coarse-textured, low-growing, stoloniferous warm-season turfgrass. It features flat, broad blades with rounded tips and a blue-green to dark green color. It forms a thick, spongy, carpet-like sward that crowds out most weeds when healthy. When left unmowed, it can reach heights of 6 to 12 inches or more, producing upright seed spikelets.
Blade Characteristics
Blades are coarse, typically 4 to 10 mm in width, flat, and folded in the bud (folded vernation). Tips are blunt and rounded. The leaf sheath is compressed and often flattened. The ligule is a fringe of hairs, and auricles are absent. The collar region is continuous and broad.
Root System
Moderately deep fibrous root system originating from nodes along the thick stolons. It establishes rapidly from sod or plugs via its stolons, has a moderate to high tendency to form thatch, and provides fair drought tolerance with moderate to slow recovery from deep drought.
Growing Information
Origin Region
Native to the Gulf of Mexico region, coastal areas of the southeastern United States, and the Caribbean; well-adapted to warm, humid tropical and subtropical climates worldwide.
Growth Habit
Stoloniferous (spreading aggressively via thick, above-ground runners called stolons) with some short rhizomes, forming a coarse, dense turf mat.
Sunlight & Water Needs
Requires full sun to moderate shade (it is the most shade-tolerant of the common warm-season turfgrasses, needing at least 4 hours of direct sun). Requires regular watering (1 inch of water per week) to maintain appearance; has moderate drought tolerance, entering dormancy during prolonged dry spells. Prefers fertile, moist, well-draining soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal mowing height is high, between 2.5 to 4 inches using a sharp rotary mower. Mowing frequency is weekly during the active growing season. Requires medium to high fertilization (2 to 5 lbs N per 1000 sq ft per year). Regular dethatching and core aeration may be needed due to thick thatch accumulation. Maintenance level is Medium-High.
Special Characteristics
Excellent shade tolerance relative to other warm-season grasses and good salt tolerance (making it ideal for coastal properties). Poor wear and traffic tolerance compared to Bermuda or Zoysia; slow to recover from severe compaction or heavy traffic damage. Susceptible to chinch bugs, sod webworms, and fungal diseases like Take-All Root Rot and Brown Patch.
Ecological Information
Introduced and naturalized widely across tropical and subtropical coastal regions. Provides good soil stabilization and erosion control on coastal slopes and sandy soils. Low wildlife food value compared to native prairie grasses, but offers ground cover and habitat for small insects and reptiles. Often grown as a monoculture lawn.