St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely 'Floratam' or 'Palmetto' based on blade width and typical southern lawn application; 'Floratam' is the most common coarse variety.
Hardiness Zones
USDA Zones 8-11. Poor cold tolerance; enters dormancy (turns brown) when temperatures drop below 55°F consistently.
About This Grass
A coarse-textured, dense turfgrass that maintains a deep blue-green color in ideal conditions. It is relatively low-growing but can reach 6-12 inches if unmowed. Features short, thick seed heads (spikes) with embedded spikelets.
Blade Characteristics
Coarse blades (>4mm wide), flat, with a distinctly rounded or 'boat-shaped' tip. Color varies from bright green to blue-green. Vernation is folded in the bud; ligule is a fringe of short hairs; auricles are absent; collar is constricted and narrow.
Root System
Fibrous and moderate depth, but primarily established through heavy surface stolons. High thatch-forming tendency; moderate establishment speed from sod or plugs.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, Caribbean, and Western Africa. Thrives in tropical and subtropical climates.
Growth Habit
Stoloniferous (spreads aggressively via above-ground runners), forming a thick, carpet-like mat.
Sunlight & Water Needs
Full sun to moderate shade (one of the most shade-tolerant warm-season grasses). Requires moderate to high water (approx. 1 inch per week). Prefers slightly acidic to neutral soil (pH 6.0-7.5).
Mowing & Maintenance
High maintenance. Ideal mowing height is 2.5 to 4.0 inches. Requires 2-4 lbs of Nitrogen per 1000 sq ft per year. Frequent dethatching may be necessary due to stolon buildup.
Special Characteristics
Excellent salt tolerance (ideal for coastal areas), high shade tolerance for a warm-season grass, poor wear tolerance compared to Bermuda, susceptible to Chinch Bugs and Large Patch (fungus).
Ecological Information
Introduced/Naturalized in the US. Provides soil stabilization in sandy coastal areas. Not considered highly invasive in managed landscapes but can crowd out native species in sensitive coastal dunes.