St. Augustine Grass
Stenotaphrum secundatum · Warm-season Perennial, C4 grass
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Likely 'Floratam' or 'Palmetto' (Standard broad-leaf turf variety)
Hardiness Zones
USDA Zones 8-11; poor cold tolerance; enters dormancy and turns brown when temperatures drop below 55°F; susceptible to winter kill in northern transition zones.
About This Grass
A coarse-textured, low-growing grass with a vibrant blue-green to dark green color. It forms a thick, spongy mat and does not produce underground rhizomes. Seed heads are inconspicuous, appearing as a flattened spike (raceme) with seeds embedded on one side.
Blade Characteristics
Coarse blades (>4mm width), flat shape with a distinct boat-shaped to rounded tip; vernation is folded; color is typically dark green; ligule is a fringe of short hairs; auricles are absent; collar is constricted and narrow.
Root System
Fibrous and relatively shallow to moderate depth (8-12 inches); primarily relies on stolons for horizontal expansion; moderate thatch builder; establishes relatively quickly from sod or plugs.
Growing Information
Origin Region
Native to the Gulf of Mexico region, West Indies, and Western Africa; well-adapted to tropical and subtropical coastal regions.
Growth Habit
Stoloniferous; spreads rapidly via thick, above-ground runners (stolons) to form a dense, carpet-like sod.
Sunlight & Water Needs
Full sun to partial shade; among the most shade-tolerant of warm-season grasses (needs 4-6 hours); high water requirement with moderate drought tolerance; prefers well-drained, fertile soils with pH 5.0-8.5.
Mowing & Maintenance
Ideal height 2.5 to 4.0 inches; weekly frequency; fertilization 2-4 lbs Nitrogen per 1000 sq ft per year; medium maintenance level; requires occasional dethatching.
Special Characteristics
Excellent salt tolerance (ideal for coastal areas); highest shade tolerance among warm-season grasses; poor wear tolerance (recovers slowly from heavy foot traffic); susceptible to Chinch bugs and Gray Leaf Spot.
Ecological Information
Native species in coastal Americas; provides soil stabilization in sandy coastal areas; can be invasive in non-native wetland ecosystems; often grown as a monoculture but can coexist with Centipede grass in some regions.