Serenoa repens Seeds | Sabal Palmetto
LATIN NAME: Serenoa repens
COMMON NAME: Saw Palmetto
Plant Profile
The two are easy to separate in the field. A cabbage palm builds one stout vertical stem, ringed with leaf scars or, on young trees, clad in the persistent leaf bases called boots that give the trunk a woven look. Its blade is costapalmate: the petiole continues into the fan as a midrib, so the leaf folds along an axis rather than opening flat. A saw palmetto spreads by underground stems into low clumps and rarely exceeds head height, and its fan lacks that midrib.
The fruit is a small black drupe borne in heavy clusters, eaten by birds and mammals that spread the seed along the coast. Its flesh contains fatty acids and phytosterols and has been surveyed as a lipid source, but the commercial phytosterol extract that dominates the supplement market comes from Serenoa repens, not from this palm. In Sabal the fat profile is dominated by lauric acid with oleic acid and a smaller proportion of palmitic acid, and the fruits of the genus have been examined for sterols including beta-sitosterol.
Cabbage palms are slow from seed and demand from coastal landscaping is steady, so clonal techniques have been explored. Embryogenic cultures can be initiated from immature inflorescences and zygotic embryos in Sabal and its relatives, allowing a uniform line of a well-formed palm to be multiplied without waiting for a seed crop. Because the palm transplants so well once sinkered, nursery practice favours deep containers that let the juvenile stem descend naturally.
Move a palm when the root ball can be lifted intact; a bigger ball is always the better choice. Set the base of the stem at grade in a hole wider than deep, backfill with sandy native soil and water in thoroughly to eliminate air pockets. Irrigate deeply but infrequently through the first season, and avoid pruning green fronds, since each one feeds the trunk below it. Watch for scale insects and palm aphids.
Science & Biotechnology
Two palms of the southeastern United States are tangled together in catalogues, and untangling them matters. Sabal palmetto is the cabbage palm: a single tall trunk rising many metres, carrying a crown of huge costapalmate fans, and it is the state tree of both Florida and South Carolina. The saw palmetto is Serenoa repens, a low creeping fan palm of the same coastal scrub, whose fruit supplies the lipid extract sold as a dietary supplement.
Uses & Benefits
The growing bud of a cabbage palm is edible, and eating it destroys the tree, because the palm has only one meristem. In Florida the harvested heart has long been cooked as swamp cabbage with fat and seasoning, and the same material is sold as heart of palm, though most commercial hearts now come from plantation-grown pejibaye. The trunk timber is a second product: the outer wood of an old cabbage palm is dense and rot-resistant, and it has served for wharf pilings, dock posts and fencing where salt water would ruin softer timber.
Growing from Seed
The most remarkable habit of Sabal palmetto is what the young plant does with its stem. Instead of growing upward, the seedling drives its stem tip downward into the soil, a geotropic behaviour known as sinkering, and only later does the growing point reverse direction and begin to rise. The result is an unusually deep root-and-stem system for the height of the palm, which is why a wild cabbage palm can be dug and transplanted at a size that would kill most palms. Self-sown volunteers appear where birds drop fruit.
Young cabbage palms keep their dead leaf bases, forming the criss-cross armour called boots. Landscape crews often strip them for a smooth trunk, while others leave them because the boots protect the stem and look natural. Either way the palm is untroubled, and the fronds cut from a mature crown give the thick thatch used in the open-sided shelters of the Seminole tradition and in much of the vernacular architecture of the warm coast.
This is one of the most salt- and wind-tolerant palms available, which is why it thrives on barrier islands and in exposed coastal gardens. Sow fresh seed in deep liners using a mix of two parts sandy loam, one part coarse sand and one part compost, and cover the seed about twice its thickness. Keep the medium evenly moist and warm, and give the seedlings full light from the start, since etiolated fan palm seedlings seldom straighten out.
Our Take
The cabbage palm is the tough coastal anchor of a warm garden: unhurried, salt-proof and almost impossible to kill once established. Use it as a specimen and let volunteer seedlings fill in a windbreak. For contrast in the same bed, plant the European fan palm for a clumping accent, the cold-hardy windmill palm for more northerly sites, and the clustering fishtail palm where winters stay mild.
Related Reading
If Saw Palmetto appeals to you, these related plants are worth a look: