Stenotaphrum secundatum Seeds | St Augustine Grass
LATIN NAME: Stenotaphrum secundatum
COMMON NAME: St Augustine Grass
Plant Profile
St Augustine grass is the lawn of the warm, humid coast, and it is a grass you almost never sow. It spreads by thick stolons that run over the surface and root at every node, forming a dense, coarse carpet of broad, blunt-ended blades in a slightly blue-green shade. It is not fine-textured, and it is not meant to be: the recommendation for it is always the same, which is that it takes heat, salt and light shade better than any other warm-season turf, and that it will cover a difficult yard in a single season given water. It grows fifteen to thirty centimetres high if unmown and needs cutting at seven to ten. The inflorescence is a ragged, one-sided spike, which gives the genus its name, and seed set is sparse in most cultivars. It is native to the Gulf Coast and the Caribbean, and it is now planted across every warm coastal region of the world.
Science & Biotechnology
Stenotaphrum secundatum is a stoloniferous perennial with 2n = 18 in most material, and the important fact about it is that the best cultivars are sterile triploids or otherwise seedless, so the turf industry propagates them by sod, plugs and sprigs rather than by seed. Floratam, the standard in Florida for decades, is a coarse, chinch-bug-resistant selection of this kind. The species is shade-tolerant for a warm-season grass because its leaves are broad and thin-walled and its photosynthetic apparatus saturates at lower light than bermudagrass, but it pays for that with poor drought recovery and low wear tolerance. It is attacked by the southern chinch bug, Blissus insularis, and by a virus that causes St Augustine decline, and both have shaped which cultivars are grown where. The one-sided raceme, with spikelets sunk into the rachis, is diagnostic for the genus.
Uses & Benefits
Its use is lawns, and in the humid subtropics it is still the default for shaded yards, coastal properties and roadsides. It holds sand on dunes and banks, and its salt tolerance makes it one of the few turfs that will grow to the beach fence. It is coarse underfoot and does not repair quickly from wear, so it is a poor choice for a sports field. The common name causes endless confusion: in Australia this grass is called buffalo grass, while in North America buffalo grass means Bouteloua dactyloides, a fine native prairie grass. The seed heads are eaten by small birds, and the dense mat shelters insects, but a lawn is not a habitat. There is no medicinal or culinary use of any consequence.
Growing from Seed
From seed, broadcast thinly over a fine, level, moist seedbed at about five grams per square metre, roll or press it in, and keep the surface damp until the seedlings are up in ten to twenty days. The seed is chaffy and light, so mix it with sand or sawdust to spread it evenly. Full sun and a soil pH near neutral suit it; do not bury the seed, since it needs light. Keep the new lawn short and water lightly and often for the first three weeks, then water deeply and less often to push the roots down. Expect a usable cover in six to eight weeks in warm weather, and do not sow below 18 degrees, because germination stalls. In most of its range, sod is faster and more reliable than seed.
Our Take
The default lawn for hot, humid, lightly shaded ground, coarse but nearly indestructible. Sow only in warm weather, or lay sod and be done with it.
Related Reading
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