St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common St. Augustine (likely 'Floratam' or 'Palmetto' based on blade width)
Hardiness Zones
USDA Hardiness Zones 8-11; poor cold tolerance; enters dormancy and turns brown when soil temperatures drop below 55°F; high heat and salt tolerance.
About This Grass
A coarse-textured, low-growing grass with a deep blue-green color. It maintains a very dense canopy when healthy and spreads rapidly via thick stolons. Seed heads are inconspicuous spikes with small embedded seeds on one side of a flattened rachis.
Blade Characteristics
Coarse blade width (8-10mm), flat shape with a distinct rounded or 'boat-shaped' tip; vernation is folded in the bud; ligule is a short fringe of hairs; auricles are absent; collar is continuous and narrowed.
Root System
Moderately deep fibrous root system originating from stolon nodes; slow to establish from seed (usually sodded or plugged); forms a thick thatch layer; good wear recovery but poor traffic tolerance.
Growing Information
Origin Region
Native to the Gulf of Mexico region, West Indies, and Western Africa; thrives in tropical and subtropical coastal climates
Growth Habit
Stoloniferous (spreads via thick, creeping above-ground runners), forming a dense, coarse mat
Sunlight & Water Needs
Full sun to moderate shade (one of the most shade-tolerant warm-season grasses); requires high water frequency and 1-1.5 inches of water per week; prefers slightly acidic to neutral pH (5.0-8.5).
Mowing & Maintenance
Ideal height 2.5–4.0 inches; requires frequent mowing to prevent thatch buildup; medium-high maintenance; needs 3-6 lbs N per 1000 sq ft annually; vertical mowing (dethatching) required periodically.
Special Characteristics
Excellent salt tolerance (ideal for coastal areas); highest shade tolerance among warm-season grasses; susceptible to Chinch Bugs and Large Patch (Rhizoctonia); low traffic tolerance compared to Bermuda.
Ecological Information
Native to coastal regions; provides excellent soil stabilization in sandy coastal soils; generally non-invasive in non-tropical zones; often grown as a monoculture turf; provides limited wildlife food value but excellent cover for small invertebrates.