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' (most common widespread commercial cultivar, known for its coarser texture, larger leaves, and bright blue-green color)
Hardiness Zones
USDA Hardiness Zones 8 through 10. Excellent heat tolerance, but poor cold tolerance (suffers winter dormancy and potential freeze damage below freezing temperatures).
About This Grass
Forms a dense, coarse-textured turf with flat, broad blades and a vibrant blue-green to apple-green color. When left unmowed, it can grow up to 6 to 12 inches tall, developing thick creeping stems. Seed heads are flattened, spike-like racemes arranged along a single axis.
Blade Characteristics
Blades are coarse (typically 5 to 10 mm wide), flat, with blunt, rounded tips. Vernation is folded in the bud. The ligule is a fringe of hairs, and auricles are absent. The collar region is continuous and broad.
Root System
Moderate root depth with a fibrous root system anchored by vigorous surface stolons. Has a high tendency to form thatch if over-fertilized. Establishes rapidly from sod or plugs.
Growing Information
Origin Region
Native to the Gulf of Mexico region, coastal areas of the southeastern United States, the Caribbean, and tropical regions worldwide. Best adapted to warm, humid tropical and subtropical climates.
Growth Habit
Aggressively stoloniferous, forming a thick, dense, carpet-like mat through above-ground runners (stolons) with short internodes.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses, requiring a minimum of 4 hours of direct sunlight). High water requirement; prone to drought stress but recovers quickly when watered. Prefers well-drained soils with a pH between 6.0 and 7.5.
Mowing & Maintenance
Mow at 2.5 to 3.5 inches high. Requires frequent mowing during the active growing season. Fertilization needs are moderate to high (2 to 5 lbs N per 1000 sq ft per year). Requires regular dethatching and high maintenance.
Special Characteristics
Moderate wear tolerance (lower than Bermuda or Zoysia), poor cold tolerance, excellent shade tolerance compared to other warm-season turfgrasses, good salt spray tolerance, aggressive weed crowding when healthy.
Ecological Information
Introduced and widely cultivated in coastal residential zones. Provides ground cover, erosion control on sandy coastal soils, and basic urban wildlife habitat, though considered invasive in certain natural wetland ecosystems outside its native range.