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 leaf width and medium-green color
Hardiness Zones
USDA Zones 8-11; poor cold tolerance; enters dormancy and turns brown below 55°F; susceptible to winter kill in northern transition zones.
About This Grass
A coarse-textured, low-growing grass with a vibrant green color. It forms a thick sod that outcompetes most weeds. When unmowed, it can reach 6-12 inches, but typically maintained at 2.5-4 inches. Seed heads are spike-like racemes with seeds embedded in a thick, flattened rachis.
Blade Characteristics
Coarse blades (8-10mm wide), flat to slightly folded, with distinctively rounded/blunt tips; vernation is folded in the bud; ligule is a fringe of short hairs; auricles are absent; collar region is broad and constricted.
Root System
Relatively shallow fibrous root system emanating from stolons; develops moderate thatch; establishment is moderate to slow via sod, plugs, or sprigs (does not produce viable commercial seed).
Growing Information
Origin Region
Natively coastal areas of the Gulf of Mexico, Caribbean, and Western Africa; well-adapted to tropical and subtropical climates
Growth Habit
Stoloniferous (spreads via thick creeping above-ground runners), forming a dense, coarse-textured mat
Sunlight & Water Needs
Prefers full sun but has the highest shade tolerance of warm-season grasses (needs 4-6 hours direct sun); high water needs; moderate drought tolerance but requires supplemental irrigation during dry spells.
Mowing & Maintenance
Ideal height: 2.5 to 4.0 inches; frequency: weekly during peak growth; fertilization: 2-4 lbs Nitrogen/1000 sq ft per year; maintenance level: Medium to High due to irrigation and pest monitoring.
Special Characteristics
Low wear tolerance compared to Bermuda; excellent shade tolerance; high salt tolerance (good for coastal areas); susceptible to Large Patch (fungus) and Chinch Bugs.
Ecological Information
Native to coastal regions; provides stabilization for sandy soils and prevents erosion; used as a primary lawn grass in the Deep South to reduce heat island effects; not generally considered invasive in managed landscapes.