St. Augustine Grass
Stenotaphrum secundatum · Warm-season perennial, C4 metabolism
Grass Family
Poaceae, Subfamily Panicoideae, Tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
Common St. Augustine / Floratam (assumed based on leaf width and color)
Hardiness Zones
USDA Hardiness Zones 8-11. Poor cold tolerance; enters dormant brown state when temperatures drop below 50°F and can be killed by hard freezes.
About This Grass
A coarse-textured, low-growing grass with a vibrant medium-to-dark green color. It forms a thick, dense sod that crowds out most weeds. When left unmowed, it can reach 6-12 inches, but it is typically maintained as a low turf. Seed heads are spike-like racemes with seeds embedded in a thick, flattened rachis.
Blade Characteristics
Coarse blade width (8-10mm), flat shape with a distinctively rounded or blunt tip. Color varies from bright green to blue-green. Vernation is folded in the bud. Ligule is a short fringe of hairs; auricles are absent; the collar is continuous and somewhat constricted.
Root System
Extensive fibrous root system reaching moderate depths; develops primarily from nodes along the stolons. High thatch-forming tendency; moderate establishment speed from sod or plugs.
Growing Information
Origin Region
Native to coastal regions of the Gulf of Mexico, Caribbean, and Western Africa; well-adapted to tropical and subtropical climates.
Growth Habit
Stoloniferous; spreads via thick, aggressive above-ground horizontal stems (stolons) to form a dense, plush carpet-like mat.
Sunlight & Water Needs
Partial Sun to Full Sun; one of the most shade-tolerant warm-season grasses (requires 4-5 hours of sun). High water needs; moderate drought tolerance but will wilt and go dormant without regular irrigation. Prefers well-drained, slightly acidic to neutral soils (pH 6.0-7.5).
Mowing & Maintenance
Ideal mowing height is 2.5 to 4.0 inches. Frequency is weekly during peak growth. Fertilization: 2-4 lbs Nitrogen per 1000 sq ft per year. High maintenance level due to water, pest monitoring, and potential for rapid thatch buildup.
Special Characteristics
Excellent shade tolerance for a warm-season grass; high salt tolerance (ideal for coastal areas). Poor wear tolerance (sensitive to heavy foot traffic); susceptible to Chinch Bugs and Large Patch (fungus).
Ecological Information
Introduced/Naturalized in the US; provides soil stabilization in coastal sandy areas. Low wildlife food value but provides cover for small invertebrates. Often grown as a monoculture; occasionally mixed with other shade-tolerant species in transition zones.