St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common variant, likely 'Floratam' or 'Palmetto'
Hardiness Zones
USDA Zones 8-11; poor cold tolerance; enters dormancy below 55°F; susceptible to winter kill in temperatures below 20°F.
About This Grass
A coarse-textured, low-growing grass that forms a thick sod. It maintains a deep green to blue-green color in warm months and goes dormant (tan) in freezing temperatures. Unmowed, it can reach 6-12 inches; seed heads are inconspicuous, thickened spikes (racemes) with embedded seeds.
Blade Characteristics
Coarse width (>4mm), flat and wide; tips are distinctly rounded or blunt (boat-shaped but broader than bluegrass); vernation is folded in the bud; ligule is a fringe of short hairs; auricles are absent; collar is constricted and smooth.
Root System
Moderately deep fibrous roots arising from thick, fleshy stolons. High thatch-forming tendency; establishment speed is moderate to fast via sod or plugs (seeds are usually sterile). Excellent wear recovery due to stoloniferous growth.
Growing Information
Origin Region
Native to coastal regions of the Gulf of Mexico, Caribbean, and Africa; well-adapted to tropical and subtropical climates.
Growth Habit
Stoloniferous (spreads aggressively via above-ground runners), forming a dense, coarse-textured mat.
Sunlight & Water Needs
Partial sun to full sun (one of the most shade-tolerant warm-season grasses); needs at least 4-5 hours of sun. Requires moderate to high watering; low drought tolerance compared to Bermuda grass; prefers well-drained, slightly acidic to neutral soils.
Mowing & Maintenance
Ideal height 2.5 to 4.0 inches; frequency weekly during peak growth; 2-4 lbs Nitrogen per 1000 sq ft per year; high dethatching needs; medium maintenance level.
Special Characteristics
High shade tolerance for a warm-season grass; excellent salt tolerance (ideal for coastal lawns); moderate wear tolerance; susceptible to Large Patch (fungus) and Chinch bugs.
Ecological Information
Introduced/Naturalized in the US; provides soil stabilization in sandy coastal areas; low wildlife value; can be invasive in native wetlands; often blended with other St. Augustine cultivars but rarely other species.