St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common or Floratam-type (likely a generic residential lawn cultivar)
Hardiness Zones
USDA 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 grass that forms a thick, dense sod. It has a distinctive blue-green to dark emerald green color when healthy. In this image, it shows significant brown dormant material or thatch underneath newer green growth. Seed heads are inconspicuous spikes with seeds embedded in one side of a flattened rachis.
Blade Characteristics
Coarse blade width (usually 8-10mm wide); blades are flat with a rounded or blunt tip; folded vernation; ligule is a short fringe of hairs; auricles are absent; collar is broad and conspicuous.
Root System
Moderately deep fibrous root system emerging from nodes on stolons; high thatch-forming tendency; moderate establishment speed from sod or plugs; good wear recovery but poor traffic tolerance.
Growing Information
Origin Region
Coastal regions of the Gulf of Mexico, Caribbean, and Western Africa; adapted to tropical and subtropical climates
Growth Habit
Stoloniferous (spreads aggressively via thick above-ground runners/stolons), mat-forming
Sunlight & Water Needs
Partial sun to full sun; one of the most shade-tolerant warm-season grasses (needs 4-6 hours); high water needs; moderate drought tolerance but wilt-sensitive; prefers well-drained slightly acidic to neutral soils.
Mowing & Maintenance
Ideal mowing height 2.5 to 4.0 inches; weekly frequency during growing season; 2-4 lbs Nitrogen per 1000 sq ft annually; high maintenance level due to water and pest needs; periodic vertical mowing required for thatch control.
Special Characteristics
Excellent shade tolerance compared to other warm-season grasses like Bermuda; high salt tolerance; susceptible to Chinch Bugs and Large Patch (rhizoctonia); poor foot-traffic tolerance.
Ecological Information
Introduced/Naturalized in the US; provides soil stabilization in coastal sandy areas; low wildlife value in turf settings; can be invasive in native riparian areas if not managed.