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', a widely used cultivar known for its coarse texture, blue-green color, and resistance to St. Augustine Decline (SAD) virus.
Hardiness Zones
USDA Hardiness Zones 8 through 10. Excellent heat tolerance, poor cold tolerance (suffers freeze damage below 25°F / -4°C). Goes dormant in colder parts of its range.
About This Grass
Forms a dense, lush, carpet-like turf with broad, flat blades. Typically maintained at 2.5 to 3 inches high, but can grow much taller if left unmowed. Color ranges from medium to dark blue-green during the growing season and turns brown/dormant under frost conditions. Produces flat spikes as seed heads at maturity.
Blade Characteristics
Coarse texture with wide blades (>4mm), flat shape, blunt or rounded tips, bright to blue-green color, folded vernation in the bud, smooth texture, distinct midrib, membranous ligule with a fringe of hairs, and absent auricles.
Root System
Moderately deep fibrous root system originating from nodes along the stolons. Prone to moderate thatch buildup. Establishes relatively quickly from sod or plugs. Forms a dense, tough sod that offers good erosion control but limited heavy wear tolerance.
Growing Information
Origin Region
Native to tropical and subtropical regions along the Gulf of Mexico, the Caribbean, and coastal areas worldwide. Thrives in warm, humid coastal climates.
Growth Habit
Aggressively stoloniferous, spreading via thick above-ground runners (stolons) that form a dense, carpet-like turf mat.
Sunlight & Water Needs
Requires full sun to moderate shade (more shade-tolerant than most warm-season grasses). Needs regular watering (1 inch per week) and has moderate drought tolerance, going into dormancy during prolonged dry spells. 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. Fertilization requires 2 to 4 lbs N per 1000 sq ft annually. Moderate to high maintenance level due to regular watering, fertilization, and pest management needs.
Special Characteristics
Moderate wear tolerance (lower than Bermuda or Zoysia), susceptible to chinch bugs, sod webworms, and large patch fungus. Good salt tolerance, making it ideal for coastal properties. Fair shade tolerance compared to other warm-season turfgrasses.
Ecological Information
Introduced/cultivated widely in coastal regions. Provides low wildlife value as a managed turf, but offers excellent soil stabilization and erosion control in sandy coastal soils. Often grown as a monoculture due to its aggressive stoloniferous spread.