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 (coarse texture, bright green color, susceptible to chinch bugs and cold)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Excellent heat tolerance, poor cold tolerance (suffers freeze damage below 25°F / -4°C), and goes dormant in winter in cooler parts of its range.
About This Grass
Forms a thick, coarse-textured, carpet-like lawn with bright to dark green color. Unmowed height can reach several inches, but maintained lawns are kept at 2.5 to 4 inches. Produces flat, upright seed heads on a flattened spike-like panicle at maturity.
Blade Characteristics
Blades are coarse (typically 4-10 mm wide), flat, with 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 broad.
Root System
Moderately deep fibrous root system originating from nodes on the thick stolons. Moderate to high thatch-forming tendency, establishes quickly from sod or plugs, and forms a very dense sod that recovers well from wear via stolon growth.
Growing Information
Origin Region
Native to tropical and subtropical regions along the Gulf of Mexico, the Caribbean, and coastal areas worldwide. Performs best in humid tropical and subtropical climates.
Growth Habit
Aggressively stoloniferous (spreading via surface runners) forming a dense, coarse turf mat, occasionally producing short rhizomes.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses, needing at least 4 hours of direct sunlight). High water needs during establishment and active growth, with moderate drought tolerance entering dormancy during severe dry spells. Prefers well-drained soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Mow at 2.5 to 4 inches using a rotary mower with sharp blades. Mowing frequency is weekly during peak summer. Fertilize at 2 to 4 lbs N per 1000 sq ft per year. Regular dethatching and core aeration as needed. Overall maintenance level is medium to high.
Special Characteristics
Good shade tolerance compared to other warm-season turfgrasses, poor traffic/wear tolerance relative to Bermuda or Zoysia, sensitive to chinch bugs and take-all root rot, moderate salt tolerance, excellent ability to crowd out weeds when dense and healthy.
Ecological Information
Introduced/cultivated turfgrass in many areas outside its native coastal habitats. Provides good soil stabilization and erosion control on coastal sites, offers micro-habitat for small ground insects and wildlife, and is typically established as a monoculture lawn.