St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Floratam (widely planted cultivar known for its coarser texture, larger leaves, and bright blue-green color)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Highly sensitive to frost and freezing temperatures, entering winter dormancy when temperatures drop below 50°F. Low cold tolerance compared to cool-season grasses.
About This Grass
Forms a dense, coarse-textured, mat-forming turf with broad blades. Typically maintained at 2.5 to 3 inches in height, but can grow much taller if left unmowed. Bright to dark green color depending on fertility and watering, turning dormant and straw-colored under prolonged cold temperatures. Produces flattened spike-like seed heads at maturity.
Blade Characteristics
Coarse width (typically 4-10 mm), flat shape with blunt, rounded tips. Color ranges from light green to bright blue-green. Vernation is folded in the bud. Ligule is a fringe of hairs. Auricles are absent. The collar region is continuous and broad.
Root System
Moderately deep fibrous root system originating from stolon nodes. Prone to thatch accumulation under high nitrogen fertilization and heavy watering. Establishes rapidly from sod or plugs due to aggressive stolon growth, but has moderate drought and traffic tolerance compared to Bermuda grass.
Growing Information
Origin Region
Native to coastal regions of the Gulf of Mexico, the Caribbean, and along the Mediterranean; widely cultivated throughout the southeastern United States, tropical regions of Central and South America, Australia, and Africa.
Growth Habit
Stoloniferous, spreading rapidly via aggressive, thick, flat surface runners (stolons) that root at the nodes, forming a dense, coarse-textured sod.
Sunlight & Water Needs
Requires full sun to partial shade (exhibits the best shade tolerance among warm-season turfgrasses). Requires regular watering, about 1 inch of water per week. Moderate to low drought tolerance, entering dormancy quickly during prolonged dry spells. Prefers well-drained soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Ideal mowing height ranges from 2.5 to 4 inches, using a sharp rotary mower to prevent tearing the wide blades. High maintenance level requiring frequent mowing during the growing season, moderate to high fertilization (2-5 lbs N per 1000 sq ft per year), regular dethatching, and monitoring for chinch bugs and fungal diseases.
Special Characteristics
Excellent shade tolerance relative to other warm-season grasses, good salt spray tolerance making it ideal for coastal areas, moderate wear tolerance, but poor recovery from heavy traffic due to stolon-based growth. Susceptible to St. Augustine decline virus, take-all root rot, and chinch bugs.
Ecological Information
Introduced and naturalized in many tropical and subtropical regions. Provides soil stabilization and erosion control in coastal sandy soils. High wildlife value for small ground-nesting animals and insects. Often managed as a monoculture lawn grass with minimal use in native prairie restoration due to its aggressive spreading nature.