St. Augustine Grass (with a patch of Crabgrass invading)
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
'Floratam' or similar common variety
Hardiness Zones
Thrives in USDA Hardiness Zones 8 through 10. Exhibits poor cold tolerance and goes dormant (turning brown) with the first frost.
About This Grass
St. Augustine grass features coarse, broad leaves with a blue-green to dark green color. It forms a dense, carpet-like turf when well-maintained. The image shows a patch of brighter green, coarser weed grass (likely large crabgrass, Digitaria sanguinalis) invading a dormant or semi-dormant St. Augustine lawn.
Blade Characteristics
Coarse blades (>4mm wide), flat, with rounded or blunt tips, folded vernation in the bud, and a membranous ligule with a fringe of hairs. The collar region is continuous.
Root System
Moderately deep fibrous root system originating from nodes on the stolons. Forms a thick thatch layer over time and establishes quickly from sod or plugs.
Growing Information
Origin Region
Gulf of Mexico region, West Indies, and tropical coastal areas worldwide; performs best in warm, humid coastal regions.
Growth Habit
Stoloniferous, spreading rapidly via thick surface runners (stolons) to form a coarse, dense turf mat.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses). Needs regular watering and moist soils; moderate drought tolerance by going dormant during severe dry spells.
Mowing & Maintenance
Ideal mowing height ranges from 2.5 to 4 inches. Requires high nitrogen fertilization during the growing season, regular watering, and periodic dethatching due to rapid stolon growth. Maintenance level is medium-high.
Special Characteristics
Moderate wear tolerance with quick recovery via stolons. Low salt tolerance compared to some warm-season grasses, excellent shade tolerance for a warm-season grass, but susceptible to chinch bugs and take-all root rot.
Ecological Information
Introduced/cultivated turfgrass in many areas, provides good soil stabilization and erosion control on coastal sandy soils, but can invade native dunes if not managed properly.