St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
'Palmetto' St. Augustine (noted for good shade tolerance and semi-dwarf growth habit)
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Poor cold tolerance; enters winter dormancy and turns brown when temperatures drop below 50°F.
About This Grass
Forms a dense, carpet-like turf with coarse-textured, flat blades. Color ranges from medium to dark green. Unmowed height can reach 6 to 12 inches, but it is typically maintained at 2.5 to 4 inches. Produces flattened seed spikes.
Blade Characteristics
Blades are coarse, greater than 4mm wide (typically 5-10mm), flat with blunt, rounded tips. Vernation is folded in the bud. Ligule is a fringe of hairs. Auricles are absent. The collar region is continuous and broad.
Root System
Moderate root depth with a fibrous system and aggressive above-ground stolons. Forms a moderate to high amount of thatch if over-fertilized. Moderate establishment speed from sod; slower from plugs.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, the Caribbean, and along the Atlantic coast; widely cultivated in tropical and subtropical regions worldwide, particularly the southeastern United States.
Growth Habit
Stoloniferous; spreads aggressively via above-ground runners (stolons) to form a thick, coarse, dense turf mat.
Sunlight & Water Needs
Requires full sun to partial shade; St. Augustine is the most shade-tolerant warm-season turfgrass. Watering needs are high during dry periods; moderate drought tolerance as it goes dormant in extreme drought.
Mowing & Maintenance
Ideal mowing height is 2.5 to 4 inches using a sharp rotary mower (dull blades fray the wide tips). Requires moderate to high maintenance, regular fertilization (2 to 5 lbs N per 1000 sq ft annually), and periodic dethatching.
Special Characteristics
Good shade and salt tolerance, making it popular for coastal lawns. Moderate wear tolerance, but slower recovery from traffic damage compared to Bermuda grass. Susceptible to chinch bugs, take-all root rot, and gray leaf spot.
Ecological Information
Introduced/cultivated widely in southern landscapes. Provides good soil stabilization and erosion control in coastal areas. Forms monocultures easily, crowding out many weeds due to its dense stoloniferous mat.