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' (most common wide-bladed, drought-resistant cultivar with purple-tinted stolons)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Low cold tolerance (susceptible to freeze damage below 20°F), goes dormant and turns straw-colored in cooler northern limits of its range.
About This Grass
Coarse-textured, dense, low-growing turfgrass with bright to medium green color. Stems are flattened and branching. Unmowed height reaches 6 to 12 inches, but typically maintained at 2.5 to 4 inches. Produces flat, spike-like seed heads in summer.
Blade Characteristics
Blades are coarse (4-10mm 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 broad, often whitish or light green.
Root System
Moderately deep fibrous root system originating from thick surface stolons (runners). Establishes quickly from sod, moderate thatch tendency, excellent sod-forming capability with good wear recovery via stolons.
Growing Information
Origin Region
Native to coastal regions of the Gulf of Mexico, Caribbean, and tropical regions worldwide; well-adapted to the southern United States
Growth Habit
Stoloniferous (spreading aggressively above ground via thick stolons), forming a dense, coarse turf mat
Sunlight & Water Needs
Requires full sun to partial shade (more shade tolerant than most warm-season grasses, needing at least 4 hours of direct sun). High water needs for best appearance, moderate drought tolerance entering dormancy during severe dry spells. Prefers moist, well-draining soils with a pH of 6.0 to 7.5.
Mowing & Maintenance
Mow at 2.5 to 4 inches using a sharp rotary mower. Mowing frequency is weekly during active summer growth. Requires medium to high maintenance, 2 to 4 lbs N per 1000 sq ft annually, periodic dethatching, and regular watering.
Special Characteristics
Excellent shade tolerance among warm-season grasses, moderate salt spray tolerance (good for coastal areas), poor traffic tolerance compared to Bermuda or Zoysia, susceptible to chinch bugs and take-all root rot, dense growth crowds out weeds effectively.
Ecological Information
Introduced and naturalized in tropical and subtropical regions globally. Provides good soil stabilization and erosion control on coastal soils, minimal wildlife forage value, occasionally considered invasive in natural tropical wetland edges.