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 St. Augustine (likely derived from 'Floratam' or 'Palmetto' based on blade width)
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 with a lush, carpet-like appearance. It has a medium-to-wide blade and a medium green to blue-green color. It stays relatively low but can become leggy if not mowed. Seed heads are inconspicuous spikes with seeds embedded in a thickened rachis.
Blade Characteristics
Coarse blade width (>4mm), folded vernation, rounded or blunt-shaped tips. Color is vibrant medium green. The ligule is a short fringe of hairs; auricles are absent; the collar is constricted and distinct.
Root System
Produces a shallow-to-moderate fibrous root system stemming from nodes on the stolons. It has high thatch-forming tendencies and moderate establishment speed via sod or plugs.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, Caribbean, and Mediterranean; widely used in the Southern US and tropical regions.
Growth Habit
Stoloniferous (spreads via thick, creeping above-ground runners); forms a dense, coarse-textured mat but lacks underground rhizomes.
Sunlight & Water Needs
Partial sun to full sun (requires at least 4-5 hours); known as one of the most shade-tolerant warm-season grasses. Needs regular watering; moderate drought tolerance but will wilt without consistent moisture.
Mowing & Maintenance
Ideal height 2.5 to 4.0 inches; weekly mowing. Fertilization 2-4 lbs N/1000 sq ft annually. Requires periodic dethatching; maintain medium maintenance level.
Special Characteristics
Excellent shade tolerance for a warm-season grass; high salt tolerance (good for coastal areas); poor wear tolerance due to succulent stolons; susceptible to Chinch bugs and Gray Leaf Spot.
Ecological Information
Introduced/Naturalized in many regions; provides good soil stabilization against erosion in coastal sandy soils; generally non-invasive in non-tropical climates; often grown as a mono-stand rather than a blend.