St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass, Erosion Control
Variety / Cultivar
Common St. Augustine (likely wild-type or 'Floratam' based on stolon thickness and internode length)
Hardiness Zones
USDA Zones 8-11; poor cold tolerance; enters dormancy and turns brown when soil temperatures drop below 55°F; prone to winter kill in northern transition zones.
About This Grass
A coarse-textured, low-growing grass with a creeping habit. It forms a thick, spongy turf with a medium to dark green color. Seed heads are inconspicuous spikes with seeds embedded in a thickened rachis.
Blade Characteristics
Coarse width (>4mm), short and wide blades with a blunt or rounded boat-shaped tip; color is medium green to blue-green; vernation is folded; ligule is a short fringe of hairs; auricles are absent; collar is constricted.
Root System
Fibrous and relatively shallow, but supported by extensive thick stolons. It has a high thatch-forming tendency and slow to moderate establishment speed from plugs or sod (rarely by seed).
Growing Information
Origin Region
Native to the coastal areas of the Gulf of Mexico, Caribbean, and Mediterranean; adapted to tropical and subtropical climates
Growth Habit
Strongly Stoloniferous; spreads aggressively above ground via thick, compressed creeping stems that root at the nodes to form a dense mat
Sunlight & Water Needs
Partial Sun to Full Sun; one of the most shade-tolerant warm-season grasses (needs 4-6 hours). High water needs; poor drought tolerance compared to Bermuda, preferring moist, well-drained soils with pH 5.0-8.5.
Mowing & Maintenance
Ideal height 2.5 to 4.0 inches; weekly mowing frequency; requires 2-4 lbs N per 1000 sq ft annually; high maintenance due to thirst and pest susceptibility; requires periodic dethatching.
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
Native to coastal regions; provides good soil stabilization against erosion; can be invasive in non-native wetland margins; often grown as a monoculture but may host various lawn-dwelling insects.