St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely 'Palmetto' or standard 'Raleigh' based on blade width and growth pattern.
Hardiness Zones
USDA Zones 8-11. Poor cold tolerance; damaged by temperatures below 10°F. Enters dormancy following the first hard frost.
About This Grass
A coarse-textured, low-growing turfgrass that forms a dense, carpet-like mat. It maintains a medium-to-dark green color during the growing season and turns brown during winter dormancy. Unmowed, it can reach 6-12 inches; if maintained, it looks lush and thick. Seed heads are spike-like racemes with seeds embedded in a thick, flattened rachis.
Blade Characteristics
Coarse (8-10mm wide), flat blades with a distinct rounded (blunt) boat-like tip. Light to medium green color. Vernation is folded in the bud. The ligule is a short fringe of hairs; auricles are absent. The collar is continuous and constricted.
Root System
Fibrous and relatively shallow compared to Bermuda, but reinforced by thick surface stolons. Forms a significant thatch layer. Establishment is moderate to fast via sod or plugs (rarely by seed). Recovery from wear is moderate.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, the Caribbean, and West Africa. Widely adapted to the humid southern United States.
Growth Habit
Stoloniferous; spreads aggressively above ground via thick, leafy runners (stolons) that root at the nodes. Does not possess rhizomes.
Sunlight & Water Needs
Partial Sun to Full Sun; it is the most shade-tolerant of the warm-season grasses (needs ~4-5 hours min). High water needs; prone to wilting during extended droughts. Prefers well-drained, slightly acidic to neutral soils (pH 6.0-7.5).
Mowing & Maintenance
Ideal height is 2.5 to 4.0 inches. Mowing frequency is weekly during peak summer. Requires 2-4 lbs of Nitrogen per 1000 sq ft annually. Dethatching is often necessary every few years. Medium maintenance level.
Special Characteristics
Excellent shade tolerance for a warm-season grass; high salt tolerance (good for coastal areas). Susceptible to St. Augustine Decline (SAD) virus, Large Patch (fungus), and Chinch bugs. Poor traffic tolerance compared to Bermuda.
Ecological Information
Introduced/Naturalized in many regions. Provides soil stabilization in coastal and humid environments. Low wildlife value in manicured lawns but provides cover in naturalized areas. Can be invasive in sensitive wetland margins if escaped.