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' (most common widespread commercial cultivar, featuring coarse, blue-green leaves and large stolons)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10 (and warm parts of Zone 11). Has very low cold tolerance; growth slows significantly below 55°F (13°C) and frost causes severe leaf damage. Goes semi-dormant or turns brown in cooler parts of its range during winter.
About This Grass
Forms a thick, carpet-like turf with coarse texture and a bright to bluish-green color. Height ranges from 2 to 3 inches when maintained as a lawn, but can grow up to 6-12 inches if unmowed. Produces flat, upright seed stalks bearing a one-sided spike-like raceme at maturity.
Blade Characteristics
Blades are coarse (typically 4-10 mm wide), flat, with blunt, 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, often whitish-green.
Root System
Moderately deep fibrous root system originating from nodes along the thick stolons. Forms a moderate to high amount of thatch over time. Establishes relatively quickly from sod or plugs. Has moderate drought tolerance and good wear recovery through rapid horizontal stolon growth.
Growing Information
Origin Region
Native to tropical regions along the Gulf of Mexico, Caribbean, and Mediterranean; widely cultivated throughout the southeastern and coastal United States, parts of Australia, and South Africa. Performs best in hot, humid tropical and subtropical climates.
Growth Habit
Stoloniferous, spreading rapidly via aggressive, thick surface runners (stolons) that form a dense, coarse-textured mat or turf.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses, needing a minimum of 4 hours of direct sunlight). Moderate to high watering needs; requires consistent moisture to look its best and has fair to moderate drought tolerance, entering dormancy during prolonged dry spells. Prefers moist, well-draining soils with a pH between 5.5 and 7.5.
Mowing & Maintenance
Ideal mowing height is 2.5 to 4 inches using a rotary mower with sharp blades to avoid tearing the coarse leaves. Mowing frequency is weekly during the active growing season. Fertilization needs are moderate to high (2 to 5 lbs N per 1000 sq ft per year depending on the cultivar and region). Regular dethatching and core aeration may be necessary due to heavy thatch accumulation. Maintenance level is Medium-High.
Special Characteristics
Poor traffic and wear tolerance compared to Bermuda or Zoysia (susceptible to damage from heavy foot traffic). Highly susceptible to certain pests such as chinch bugs and sod webworms, and fungal diseases like Take-All Root Rot and large patch. Low salt tolerance makes it popular for coastal properties. Does not tolerate heavy shade well, though it is the most shade-tolerant warm-season grass.
Ecological Information
Introduced/cultivated across many tropical and subtropical regions globally. Provides ground cover and erosion control, especially in sandy coastal soils. Serves as a habitat and food source for various insects and ground-nesting birds. Can become invasive or weed-like in tropical ecosystems outside of cultivation.