St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Floratam (coarse texture, bright green color, well-adapted to Florida)
Hardiness Zones
USDA Hardiness Zones 8 through 10. Exhibits poor cold tolerance and will suffer frost or freeze damage below 25°F. Goes dormant and turns brown in cooler northern ranges.
About This Grass
St. Augustine grass is a coarse-textured, low-growing warm-season turfgrass forming a thick, dense carpet. It features flat blades with blunt, rounded tips and a bright blue-green to dark green color. Unmowed height reaches 6 to 12 inches, but it is typically maintained at 2.5 to 4 inches. When mature, it produces flattened, spike-like seed heads.
Blade Characteristics
Blades are broad and coarse, typically 4 to 10 mm in width, flat, with distinct parallel veins and prominent rounded or blunt (boat-shaped to rounded) tips. Vernation is folded in the bud. The ligule is a fringe of hairs, auricles are absent, and the collar is continuous and broad.
Root System
Moderately deep fibrous root system combined with aggressive above-ground stolons. Forms a moderate to heavy thatch layer. Establishes rapidly from sod or plugs. Moderate drought tolerance; goes dormant during severe droughts.
Growing Information
Origin Region
Native to the Gulf of Mexico region, coastal areas of the southeastern United States, and the Caribbean. Cultivated widely in warm, humid coastal regions worldwide.
Growth Habit
Stoloniferous, spreading rapidly via robust above-ground runners (stolons) to form a dense, coarse turf mat.
Sunlight & Water Needs
Requires full sun to partial shade; it is the most shade-tolerant warm-season turfgrass. Needs moderate to high watering (approximately 1 inch of water per week) to maintain green color. Prefers moist, fertile soils with a pH of 5.5 to 7.0.
Mowing & Maintenance
Maintain at a relatively high mowing height of 2.5 to 4 inches using a sharp rotary mower. Mower frequency is weekly during the active growing season. Requires medium to high nitrogen fertilization (2 to 5 lbs N per 1000 sq ft per year). Regular dethatching and aeration may be necessary due to rapid stolon growth.
Special Characteristics
Good shade tolerance for a warm-season grass, excellent salt spray tolerance making it ideal for coastal lawns. Moderate traffic and wear tolerance with good recuperative ability via stolons. Susceptible to chinch bugs, sod webworms, and large patch fungus.
Ecological Information
Introduced and naturalized in many tropical and subtropical regions. Provides ground cover and soil stabilization in coastal and urban environments, controls erosion, and offers limited habitat for insects and small urban wildlife. Often grown as a monoculture lawn due to its dense, aggressive spreading nature.