St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass
Hardiness Zones
USDA Hardiness Zones 8 through 10. Excellent heat tolerance, poor cold tolerance (susceptible to frost damage and winter kill below 25°F). Not suited for the transition zone except in mild coastal microclimates.
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Variety / Cultivar
Floratam (widely planted cultivar known for its coarse texture and purple stolons)
About This Grass
Forms a dense, coarse-textured, apple-green to blue-green lawn that spreads vigorously via flat stolons. When unmowed, it can grow up to 6 to 12 inches tall with upright flower spikes, but it is typically maintained low. Shows winter dormancy (turns brown or straw-colored) in cooler parts of its range.
Blade Characteristics
Blades are coarse (typically 4-10 mm wide), flat, with blunt, rounded tips. Vernation is folded in the bud. Ligule is a fringe of hairs. Auricles are absent. The collar region is continuous and narrow.
Root System
Moderately deep fibrous root system originating from stolon nodes. Forms a thick thatch layer if not managed properly. Fast establishment from sod, moderate to slow from plugs; moderate drought tolerance with poor recovery compared to some warm-season grasses.
Growing Information
Origin Region
Native to tropical and subtropical coastal regions around the Gulf of Mexico, Caribbean, and the Mediterranean; widely cultivated in the southern United States and tropical regions worldwide.
Growth Habit
Stoloniferous, spreading rapidly via thick surface runners (stolons) to form a dense, coarse-textured turf mat.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses like Bermuda). Needs about 1 inch of water per week. Moderate to high water requirement during active growth; moderate drought tolerance, entering dormancy during severe dry spells.
Mowing & Maintenance
Ideal mowing height is 2.5 to 4 inches. High mowing encourages deep roots and shade tolerance. Requires medium to high maintenance, including regular fertilization (2-4 lbs N per 1000 sq ft annually), frequent dethatching due to rapid stolon production, and periodic weed and insect management.
Special Characteristics
Moderate traffic and wear tolerance (less than Bermuda or Zoysia), poor cold tolerance, excellent shade tolerance for a warm-season grass, moderate salt tolerance (well-suited for coastal properties), and good ability to crowd out weeds when dense and healthy.
Ecological Information
Introduced and naturalized in many tropical and subtropical areas. Provides limited wildlife food value compared to native prairie grasses, but offers good soil stabilization and erosion control in coastal sandy soils. Often grown as a monoculture lawn.