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 (goes dormant and can suffer frost damage below freezing). Not suitable for the cool northern transition zones.
Grass Family
Poaceae, subfamily Panicoideae, tribe Panicae
Variety / Cultivar
Floratam, a widely planted cultivar known for its coarse texture, blue-green color, and resistance to St. Augustine Decline (SAD) virus.
About This Grass
A coarse-textured, dense turfgrass with broad flat blades and a vibrant blue-green to dark green color. It typically grows low to the ground and forms a thick, spongy sod. Unmowed, it can reach heights of 6 to 12 inches but is typically maintained much lower. Seed heads are flattened spikes.
Blade Characteristics
Blades are coarse (>4-10mm wide), flat with rounded or blunt tips, folded in the bud (vernation), smooth texture with light green to blue-green color. Features a short membranous ligule with a fringe of hairs, continuous collar, and absent auricles.
Root System
Moderate root depth with a fibrous root system anchored by thick stolons. High tendency to produce thatch if over-fertilized. Fast establishment from sod, moderate from plugs; forms a very dense sod that limits weed intrusion.
Growing Information
Origin Region
Native to tropical and subtropical regions along the Gulf of Mexico, the Caribbean, and coastal areas worldwide. Performs best in warm, humid coastal climates.
Growth Habit
Stoloniferous, spreading aggressively via robust above-ground runners (stolons) to form a dense, carpet-like turf.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses, needing at least 4 hours of direct sun). High water needs during active growth, moderate drought tolerance (enters dormancy during severe dry spells). Prefers moist, well-draining soils with a pH of 5.5 to 7.5.
Mowing & Maintenance
Mow at 2.5 to 3.5 inches high using sharp blades to prevent tearing. Requires medium to high maintenance, frequent watering, and 2 to 4 lbs of nitrogen per 1000 sq ft annually. Regular dethatching and core aeration are often necessary due to thick thatch accumulation.
Special Characteristics
Moderate wear tolerance (does not recover from traffic as fast as Bermuda or Zoysia), poor cold tolerance, good salt spray tolerance (ideal for coastal properties), excellent shade tolerance for a warm-season grass, and aggressive growth habit crowds out weeds effectively.
Ecological Information
Introduced to many areas outside its native range for turf use. Provides limited wildlife value compared to native grasses, though it offers good soil stabilization and erosion control in coastal sandy soils. Often grown as a monoculture lawn.