Stenotaphrum secundatum Seeds | Saint Augustine Grass
LATIN NAME: Stenotaphrum secundatum
COMMON NAME: St. Augustine Grass
Plant Profile
Stenotaphrum secundatum is a creeping perennial grass of the Americas, known as St Augustine grass, with broad, flat, blunt-tipped leaves and long stolons that root at every node. It forms a dense, coarse turf that is common on lawns and roadsides throughout the warm, humid subtropics.
It is native to the Gulf Coast, the Caribbean and parts of South America, and it has been carried around the warm world as a lawn grass. It is salt-tolerant, shade-tolerant and fast to cover ground, which is why it is planted where other turf grasses fail. The leaf tips are blunt and often folded, and the surface has a slightly coarse feel compared with finer lawn grasses.
Science & Biotechnology
The grass spreads almost entirely by stolons rather than seed, and most lawn cultivars are propagated as sod or plugs. Seed production is limited because the inflorescence is short and the seed set is poor, though the species does set some seed in the tropics.
Its shade tolerance comes from a low light compensation point and from the ability to elongate leaves in shade, which keeps the lawn green under trees where Bermuda grass thins out. The trade-off is coarse texture and poor wear tolerance: St Augustine is easily torn by heavy use and slow to recover from damage. The grass also tolerates salt spray and poor, sandy soil, which is why it is the standard turf for coastal parks in Florida and the Caribbean. Chinch bugs are the main pest, and a lawn that yellows in patches in summer should be checked at the base of the grass, where the insects feed.
Uses & Benefits
The grass is used for lawns, for roadsides and for stabilising banks, particularly near the coast where salt spray kills other turf. It is also planted between trees in orchards in Florida and the Caribbean.
Its main pest is the chinch bug, which can kill a lawn in patches within a week in hot, dry weather. Large patch disease and grey leaf spot are the common fungal problems, both encouraged by overwatering and by mowing too low. It should be mown at seven to ten centimetres, higher than most grasses.
Growing from Seed
Sod or plugs are the practical route: lay sod on prepared ground in spring or autumn, keep it moist for two weeks, and it knits within a month. Seed is rarely available and slow to establish.
The grass wants sun or part shade, frequent watering in sand and less on clay, and a pH between 6 and 7.5. Fertilise lightly in spring and again in midsummer, and avoid heavy nitrogen, which invites disease. In frost-prone areas it browns at the first freeze and greens again late in spring, so it is a grass for the subtropics rather than the temperate zone.
Our Take
The lawn grass for shade and salt in the humid subtropics, coarse and easily damaged but willing to grow where finer grasses give up.
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