St. Augustine Grass
Stenotaphrum secundatum · Warm-season, Perennial, C4 grass
Grass Family
Poaceae, subfamily Panicoideae, tribe Paniceae
Grass Category
Lawn/Turf Grass
Variety / Cultivar
'Floratam' (most common widespread variety characterized by coarse texture and purplish stolons)
Hardiness Zones
USDA Hardiness Zones 8 through 10, with some cultivars performing in warm parts of Zone 7. Highly sensitive to cold temperatures and frosts, entering winter dormancy where it turns straw-brown.
About This Grass
Forms a dense, coarse-textured, bright to medium green turf with a prostrate growth habit. It grows aggressively via flat, thick stolons. Unmowed, it can reach heights of 6 to 12 inches or more, but is typically maintained much lower. Seed heads are flattened spikes with spikelets embedded in a zigzag axis.
Blade Characteristics
Coarse blades, typically 4-10 mm wide, flat with rounded or obtuse tips. Color ranges from light green to medium blue-green. Vernation is folded in the bud. Ligule is a fringe of hairs, auricles are absent, and the collar region is continuous and broad.
Root System
Moderate root depth with a fibrous root system anchored by thick stolons. Moderate to high thatch-forming tendency, especially with excess nitrogen and water. Establishes rapidly from sod or plugs.
Growing Information
Origin Region
Native to the coastal regions of the Gulf of Mexico, Caribbean, and Mediterranean; widely cultivated in warm, humid tropical and subtropical climates globally, especially the southern United States.
Growth Habit
Stoloniferous, spreading rapidly via aggressive, thick above-ground runners (stolons) to form a dense, coarse turf mat.
Sunlight & Water Needs
Requires full sun to partial shade (more shade-tolerant than most warm-season grasses). High water requirement; moderate drought tolerance by going dormant, but thrives with regular moisture. Prefers moist, fertile soils with a pH of 5.5 to 7.5.
Mowing & Maintenance
Ideal mowing height is 2.5 to 3.5 inches using a sharp rotary mower. Mowing frequency is weekly during the active growing season. Fertilization needs are moderate to high (2 to 4 lbs N per 1000 sq ft per year). Requires periodic dethatching and core aeration. Maintenance level is medium.
Special Characteristics
Poor to moderate wear and traffic tolerance due to its coarse, spongy stolons. Susceptible to chinch bugs, sod webworms, and diseases like Take-All Root Rot and Gray Leaf Spot. Good salt tolerance, making it ideal for coastal areas. Excellent shade tolerance relative to other warm-season turfgrasses.
Ecological Information
Introduced/cultivated widely in coastal urban and suburban landscapes. Provides low wildlife value compared to native prairies, but offers effective soil stabilization and erosion control on coastal sandy soils. Filter runoff well due to dense mat formation.