St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely 'Floratam' or 'Palmetto' (most common residential cultivars)
Hardiness Zones
USDA Zones 8-11. Poor cold tolerance; enters dormancy and turns brown when soil temperatures drop below 55°F.
About This Grass
A coarse-textured, low-growing grass with a bright green to blue-green color. It maintains a very dense sod. When unmowed, it can reach 6–12 inches. Seed heads form a flattened spike (spate) with small seeds embedded on one side.
Blade Characteristics
Coarse blade width (>4mm), predominantly flat shape with a distinctively rounded or blunt tip. Vernation is folded in the bud. Color is medium to dark green. It has a short hairy ligule and no auricles.
Root System
Moderately deep fibrous root system emerging from stolon nodes. High thatch-forming tendency due to stolon density. Establishment speed is moderate to fast via sod or plugs.
Growing Information
Origin Region
Coastal regions of Africa, North America, and South America; thrives in tropical and subtropical climates.
Growth Habit
Stoloniferous; spreads aggressively via thick, above-ground runners (stolons) to form a dense, spongy mat.
Sunlight & Water Needs
Partial Sun to Full Sun (typically needs 4-6 hours); one of the most shade-tolerant warm-season grasses. High water needs; poor drought tolerance compared to Bermuda.
Mowing & Maintenance
High maintenance. Ideal height is 2.5 to 4.0 inches. Requires frequent mowing and 2-4 lbs Nitrogen per 1000 sq ft annually. Vulnerable to thatch buildup requiring vertical mowing.
Special Characteristics
Excellent shade tolerance for a warm-season grass, high salt tolerance (ideal for coastal areas), and provides excellent weed suppression due to its density. Susceptible to Chinch bugs and Large Patch disease.
Ecological Information
Introduced/Naturalized in the US. Good for soil stabilization in coastal ecosystems. Moderate wildlife value. Often grown as a monoculture but may host various insects and larvae.