St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Lawn, Turf, and Erosion Control Grass
Variety / Cultivar
Common or Floratam-type (notable for wide, coarse blades and purple-tinged stolons)
Hardiness Zones
USDA Zones 8-11. Poor cold tolerance; enters dormancy (turns brown) when temperatures stay consistently below 55°F; prone to winter kill in temperatures below 20°F.
About This Grass
A coarse-textured, low-growing grass that forms a thick, carpet-like sod. Typically maintained at 2.5–4 inches; foliage is medium to dark green. Seed heads are inconspicuous, featuring spikes with seeds embedded on one side of a flattened rachis.
Blade Characteristics
Coarse blades (8-10mm wide), flat, with a distinctly rounded or 'boat-shaped' blunt tip. Vernation is folded in the bud. Color is typically a vibrant medium green. It lacks auricles and has a short, fringe-like hairy ligule.
Root System
Fibrous root system with moderate depth; primarily spreads and anchors via extensive stolons. Develops significant thatch over time. Fast establishment via sod or plugs, but slow from seed. High wear recovery.
Growing Information
Origin Region
Native to coastal areas of the Gulf of Mexico, Caribbean, and West Africa; thrives in tropical and subtropical moist coastal climates.
Growth Habit
Creeping habit, strongly stoloniferous (spreads via above-ground runners), forming a dense, coarse mat.
Sunlight & Water Needs
Prefers Full Sun but has some of the best shade tolerance among warm-season grasses (needs 4-6 hours). High water requirement; moderate drought tolerance but will wilt without regular irrigation in sandy soils.
Mowing & Maintenance
Ideal height: 2.5–4.0 inches. Weekly mowing frequency during peak summer. Fertilization: 2-4 lbs N per 1000 sq ft annually. High maintenance due to irrigation and potential for 'St. Augustine Decline' and thatch buildup.
Special Characteristics
Excellent shade tolerance compared to Bermuda; high salt tolerance (ideal for coastal yards); moderate wear tolerance; susceptible to Large Patch (fungus) and Chinch Bugs.
Ecological Information
Introduced/Naturalized in many regions. Excellent for soil stabilization and erosion control in wet, coastal areas. Provides dense cover for small insects but can be invasive in native ecosystems if escaped from lawns.