St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, Panicoideae, Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely 'Floratam' or 'Palmetto' (Standard broad-leaf cultivar)
Hardiness Zones
USDA Hardiness Zones 8-10; poor cold tolerance; enters dormancy and turns brown when soil temperatures drop below 55°F.
About This Grass
A coarse-textured, low-growing turfgrass that forms a thick, carpet-like sod. It is deep green to blue-green in color and retains its color well into the fall compared to other warm-season grasses. It produces short, spike-like seed heads but is primarily established vegetatively.
Blade Characteristics
Coarse blade width (>4mm), folded vernation, rounded or blunt tips, and a smooth surface. The collar is continuous and somewhat constricted; the ligule is a short fringe of hairs (approx. 0.5mm); auricles are absent.
Root System
Extensive fibrous root system originating from stolon nodes; moderate depth; high thatch-forming tendency; slow to moderate establishment speed; moderate wear recovery due to stolon-only growth.
Growing Information
Origin Region
Native to the Gulf of Mexico region, West Indies, and Western Africa; common in humid subtropics.
Growth Habit
Stoloniferous (spreads aggressively via thick above-ground runners), forming a dense, coarse mat.
Sunlight & Water Needs
Full sun to partial shade (one of the most shade-tolerant warm-season grasses); needs minimum 4-6 hours of sun; high water requirement; needs 1 inch of water per week; prefers pH 5.0 to 8.5.
Mowing & Maintenance
Mowing height 2.5 to 4 inches; weekly frequency; fertilization 2-4 lbs N per 1000 sq ft per year; moderate-to-high maintenance; requires periodic vertical mowing to manage thatch.
Special Characteristics
Excellent shade tolerance for a warm-season grass; high salt tolerance (coastal suitable); susceptible to Chinch Bugs and Large Patch (Rhizoctonia); poor traffic tolerance due to fleshy stolons.
Ecological Information
Introduced/Naturalized in the US; provides soil stabilization in sandy coastal areas; low wildlife value in managed lawns; not considered invasive in urban settings but can displace native vegetation in moist coastal habitats.