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 wide-bladed cultivar with good drought and insect resistance)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10 (and into 11). Has poor cold tolerance compared to Bermuda or Zoysia; susceptible to freezing damage below 25°F. Excellent heat tolerance.
About This Grass
St. Augustine grass forms a dense, carpet-like turf with coarse-textured, flat blades. It features a bright blue-green to dark green color during the growing season and goes into winter dormancy (turning straw-colored) in cooler parts of its range. Unmowed, it can grow up to 6-12 inches tall, but it is typically maintained much lower. Seed heads are flattened spikes.
Blade Characteristics
Blades are coarse (typically 4-10mm wide), flat, with rounded to somewhat blunt tips. Vernation is folded in the bud. Ligule is a fringe of hairs. Auricles are absent. The collar region is continuous and broad, often whitish.
Root System
Moderate root depth (typically 6-24 inches depending on soil compaction), fibrous root system spreading primarily via thick above-ground stolons (runners). Moderate to high thatch-forming tendency. Fast establishment from sod, slow from plugs.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, Caribbean, and Mediterranean; widely cultivated in warm-temperate and tropical regions, particularly the Southern United States
Growth Habit
Aggressively stoloniferous and rhizomatous, forming a thick, coarse, and dense mat-forming sod
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses, needing at least 4 hours of direct sun). High water needs during establishment and hot periods; moderate drought tolerance by entering dormancy. Prefers moist, well-draining soils with a pH of 6.0 to 7.5.
Mowing & Maintenance
Ideal mowing height ranges from 2.5 to 4 inches. Mowing frequency is weekly during the active growing season. Fertilization requires 2 to 4 lbs N per 1000 sq ft per year. High maintenance level due to regular watering, mowing, and dethatching needs.
Special Characteristics
Moderate traffic and wear tolerance (less than Bermuda or Zoysia, slower recovery from damage). Good salt tolerance, making it ideal for coastal areas. Moderate shade tolerance. Prone to chinch bugs, sod webworms, and fungal diseases like Take-All Root Rot and Large Patch.
Ecological Information
Introduced and naturalized in many coastal regions globally. Provides soil stabilization and erosion control in sandy coastal soils. Valued for ground cover and residential lawns, offering limited wildlife value primarily as protective ground cover.