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 (widely cultivated variety known for its large, coarse texture and purplish stolons)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Excellent heat tolerance, poor cold tolerance (susceptible to frost damage and enters winter dormancy in cooler zones, turning brown).
About This Grass
Forms a thick, carpet-like turf with coarse texture and bright to dark blue-green color. Unmowed height can reach 6 to 12 inches, typically maintained at 2.5 to 4 inches. Produces flat, spike-like seed heads on terminal stalks at maturity.
Blade Characteristics
Coarse blade width (greater than 5mm), flat shape with blunt, rounded tips. Color ranges from light to dark blue-green. Vernation is folded in the bud. Ligule is a fringe of hairs. Auricles are absent. Collar region is continuous and narrow.
Root System
Moderately deep fibrous root system originating from stolon nodes. Forms a thick thatch layer if over-fertilized. Moderate establishment speed from sod or plugs; excellent sod-forming capability for erosion control.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, Caribbean, and Mediterranean. Widely cultivated in tropical and subtropical climates globally, especially the southern United States.
Growth Habit
Stoloniferous, spreading rapidly via aggressive, flat above-ground runners (stolons) to form a dense, coarse turf mat.
Sunlight & Water Needs
Performs best in full sun but has the best shade tolerance among warm-season turfgrasses (requires at least 4 hours of direct sun). High water needs during active growth; moderate drought tolerance by entering dormancy under severe dry conditions. Prefers well-drained soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal mowing height is 2.5 to 4 inches using a sharp rotary mower. Medium-high maintenance. Requires 2 to 4 lbs of nitrogen per 1,000 sq ft annually. Regular dethatching and occasional core aeration needed due to heavy thatch production.
Special Characteristics
Moderate wear tolerance (lower than Bermuda or Zoysia), poor cold tolerance, excellent shade tolerance for a warm-season grass, good salt spray tolerance making it ideal for coastal areas. Recovers moderately well from damage via stolon growth.
Ecological Information
Introduced/cultivated turfgrass in many regions. Provides moderate wildlife habitat and excellent soil stabilization for coastal and erosion-prone sandy soils. Can become invasive in natural tropical wetlands if escaped.