St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
AI-generated identification · may be incorrect
Grass Category
Lawn/Turf Grass
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Excellent heat tolerance, poor cold tolerance (suffers injury below 25°F). Commonly grown in the southern United States and transition zones near coastal areas.
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Variety / Cultivar
'Floratam', a widely used cultivar known for its coarse texture, blue-green color, and resistance to St. Augustine Decline (SAD) virus.
About This Grass
Forming a dense, carpet-like turf with coarse, flat blades. Typically maintained at 2.5 to 3 inches, but can grow up to 6 inches or higher if unmowed. Bright to dark green or blue-green color in summer, going dormant and turning brown with the first hard frost. Features a flattened inflorescence spike (seed head) with spikelets embedded in a flattened axis.
Blade Characteristics
Coarse texture with blade width generally greater than 5mm (ranging from 4 to 10mm). Blades are flat with rounded to slightly blunt tips, folded in the bud (vernation). Ligule is a fringe of hairs. Auricles are absent. Distinct collar region with the blade often continuous with the sheath.
Root System
Moderately deep fibrous root system originating from nodes along the stolons. Forms a moderate to heavy thatch layer. Fast establishment from plugs or sod, but slow from seed. Moderate drought tolerance, recovers well from wear via stolon growth.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, the Caribbean, and along the Mediterranean. Performs best in warm, humid subtropical and tropical climates.
Growth Habit
Stoloniferous, spreading aggressively 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 most warm-season grasses requiring a minimum of 4 hours of direct sun). High water needs during active growth periods; moderate drought tolerance by entering dormancy. Prefers moist, well-draining 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. Mowing frequency is weekly during peak growing season. High maintenance regarding fertilization (2 to 4 lbs N per 1000 sq ft per year). Requires periodic dethatching and core aeration. Medium-high overall maintenance level.
Special Characteristics
Good shade tolerance compared to other warm-season grasses. Moderate to low wear/traffic recovery due to stoloniferous spread. Moderate salt tolerance making it popular for coastal lawns. Susceptible to chinch bugs, take-all root rot, and large patch disease.
Ecological Information
Introduced and naturalized in many tropical and subtropical regions. Provides good soil stabilization and erosion control on coastal sites. Moderate wildlife value for ground-foraging birds and insects. Not considered invasive in managed lawns, but can spread into natural areas in tropical climates.