St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Excellent heat tolerance, but poor cold tolerance, going dormant and turning brown with the first hard frost. Not suitable for the northern transition zone.
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Variety / Cultivar
'Floratam' (most common widely adapted cultivar known for its coarse texture, blue-green color, and relatively long internodes)
About This Grass
St. Augustine grass is a coarse-textured, dense, stoloniferous warm-season turfgrass featuring broad, flat leaf blades with blunt tips. It forms a lush, dark green to blue-green turf that grows aggressively in warm weather. When unmowed, it can reach heights of 6 to 12 inches. Seed heads appear as a flattened spike-like raceme.
Blade Characteristics
Blades are broad (typically 4 to 10 mm wide), flat, with rounded or blunt tips. Vernation is folded in the bud. The ligule is a fringe of hairs. Auricles are absent. The collar region is continuous and broad, often whitish or light green.
Root System
Moderate depth fibrous root system anchored by thick surface stolons. Forms a dense, spongy sod. Moderate to high thatch-forming tendency due to rapid stolon growth, requiring periodic dethatching. Establishes relatively quickly from sod.
Growing Information
Origin Region
Native to coastal regions of the Gulf of Mexico, Caribbean, and tropical regions worldwide. Cultivated extensively throughout the southern United States and tropical climates globally.
Growth Habit
Stoloniferous, spreading rapidly by robust surface runners (stolons) to form a thick, coarse, carpet-like turf.
Sunlight & Water Needs
Requires full sun to partial shade; St. Augustine is the most shade-tolerant warm-season grass. High water needs during active growth periods to maintain a lush appearance. Moderate to low drought tolerance (enters dormancy during severe drought). Prefers moist, well-draining soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal mowing height ranges from 2.5 to 4 inches using a rotary mower with sharp blades to prevent tearing the coarse leaves. Mowing frequency is weekly during the peak growing season. Fertilization needs are moderate to high (2 to 4 lbs N per 1000 sq ft per year). Requires medium-high maintenance.
Special Characteristics
Moderate traffic and wear tolerance, recovering well via stolons though slower than Bermuda grass. Susceptible to chinch bugs, sod webworms, take-all root rot, and gray leaf spot. Excellent salt tolerance, making it ideal for coastal properties. Poor cold tolerance.
Ecological Information
Introduced and naturalized in many coastal subtropical regions. Provides ground cover and erosion control, especially in sandy coastal soils. Supports local urban wildlife habitat, though primarily managed as a cultivated amenity turf.