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 8-10. Poor cold tolerance; damaged by frosts below freezing and goes completely dormant or dies back in extended cold snaps. Not suited for the transition zone.
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Variety / Cultivar
Common St. Augustine ('Floratam' or 'Palmetto' are common cultivated varieties known for wider/narrower blades and color depth)
About This Grass
St. Augustine grass is a lush, coarse-textured turfgrass with wide, flat blades and blunt, rounded tips. It forms a dense, carpet-like sward that crowds out many weeds. Color ranges from medium to dark blue-green, turning brown and going dormant during winter freezes. When unmanaged, it can grow up to 6-12 inches tall, but is typically maintained at 2.5-4 inches. The inflorescence is a one-sided spike with spikelets embedded alternately along a flattened rachis.
Blade Characteristics
Blades are coarse, greater than 4mm in width, flat, and feature blunt, rounded tips. Vernation is folded in the bud. The ligule is a fringe of hairs, and auricles are absent. The collar region is continuous and often broad.
Root System
Moderate depth root system with extensive stolon network. Forms a dense sod and moderate thatch layer if over-fertilized. Moderate establishment speed from sod; slower from plugs.
Growing Information
Origin Region
Native to tropical and subtropical coastal regions around the Gulf of Mexico, Caribbean, and West Africa. Widely cultivated in the Southern United States, parts of California, and tropical regions globally.
Growth Habit
Stoloniferous, spreading rapidly via thick, above-ground runners (stolons) to form a dense, coarse-textured turf mat.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than many other warm-season grasses like Bermuda, needing at least 4-6 hours of sun). High water requirement; moderate drought tolerance by entering dormancy. Prefers well-drained soils with a pH of 6.0 to 7.5.
Mowing & Maintenance
Ideal mowing height is 2.5 to 4 inches using a sharp rotary mower. Mow every 7-10 days during the growing season. Requires 2-4 lbs of nitrogen per 1000 sq ft annually. High maintenance level due to disease susceptibility, watering needs, and fast spreading stolons.
Special Characteristics
Moderate to low wear/traffic tolerance compared to Bermuda or Zoysia; repairs slowly from heavy damage. Susceptible to chinch bugs, sod webworms, and fungal diseases like Take-All Root Rot and Large Patch. Excellent salt tolerance, making it ideal for coastal properties. Good shade tolerance for a warm-season grass.
Ecological Information
Introduced species in many non-native regions. Provides good soil stabilization and erosion control on coastal sites. High wildlife value for local insects and small ground-dwelling animals within its turf canopy. Low invasive potential outside of landscaped zones, though it can creep into flower beds.