St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Palmetto or Floratam (common commercial cultivars)
Hardiness Zones
USDA Hardiness Zones 8 to 11. Low cold tolerance, goes dormant and turns brown with the first hard frost, susceptible to freeze damage in northern transition zones.
About This Grass
Forms a dense, carpet-like turf with coarse-textured, flat blades. Bright to dark green color depending on fertility and management. Unmowed height can reach 6 to 12 inches, while maintained height is typically 2.5 to 4 inches. Produces a flattened spike-like seed head at maturity.
Blade Characteristics
Coarse width (>4mm), flat shape with blunt or rounded tips, bright to medium green color, rolled in the bud (vernation). Ligule is a fringe of hairs, auricles are absent, and the collar region is continuous.
Root System
Moderately deep fibrous root system originating from nodes on thick stolons. Moderate establishment speed from sod or plugs, forms a thick thatch layer over time, and spreads aggressively horizontally.
Growing Information
Origin Region
Native to coastal regions worldwide in tropical and subtropical areas, well-adapted to the southern United States
Growth Habit
Stoloniferous, spreading rapidly via thick above-ground runners to form a dense, coarse-textured sod
Sunlight & Water Needs
Prefers full sun but has the best shade tolerance among warm-season grasses (requires at least 4 hours of direct sun). High water needs during active growth, moderate drought tolerance by going dormant under severe drought.
Mowing & Maintenance
Ideal mowing height is 2.5 to 4 inches using a sharp rotary mower. Medium to high maintenance level requiring regular fertilization, watering, and occasional dethatching due to heavy stolon and thatch accumulation.
Special Characteristics
Good shade tolerance for a warm-season grass, moderate wear tolerance but slow recovery from severe damage compared to Bermuda, susceptible to chinch bugs and large patch disease, poor salt spray tolerance relative to some coastal grasses.
Ecological Information
Introduced and naturalized in many tropical and subtropical regions. Provides excellent soil stabilization and erosion control on coastal sites, forms dense monocultures that outcompete most weeds, and offers limited wildlife cover.