Pandanus tectorius Seeds | Screwpine
LATIN NAME: Pandanus tectorius
COMMON NAME: Screwpine, Thatch Screwpine
Plant Profile
Screwpine is a tree that looks as if it were designed by someone who had heard about trees but had never actually seen one. It stands on a cone of stout prop roots, the trunk branching as it rises, and the leaves spiral up the stems in a tight three-ranked corkscrew — hence the name. Each leaf is a metre or more of stiff, sword-shaped blade with saw-toothed edges and a pale midrib. Male and female flowers sit on separate trees; the male inflorescence is a long, fragrant white bract, the female a cluster of carpels that swells into a heavy, segmented fruit the size of a football, turning orange as it ripens. It grows along the coasts of the Indo-Pacific from Hawaii to northern Australia, almost always within reach of salt spray, and it is one of the few large trees that will grow on pure beach sand.
Science & Biotechnology
The fruit is a syncarp: dozens of wedge-shaped drupes fused into one head, each with a fibrous husk around a hard stone. That structure explains both the dispersal and the taxonomy — Pandanus is notoriously difficult because the species hybridise wherever their ranges touch, and P. tectorius itself is probably a species complex rather than a single entity. The spiral leaf arrangement is one of the cleanest examples of phyllotaxis in a woody plant, and the prop roots are a study in how a tree solves the problem of anchorage in loose, shifting sand. The genus is also chemically distinctive: the leaves of the culinary pandan, P. amaryllifolius, carry 2-acetyl-1-pyrroline, the same compound that gives basmati rice its aroma, though the leaves of P. tectorius are milder and are used for scenting rather than for flavour.
Uses & Benefits
The specific epithet means roofing, and that has been the plant’s principal job for millennia: the leaves are cut, dried, split and laid in overlapping thatch that lasts for years and sheds tropical rain. The same leaves are plaited into mats, baskets, sails and fans across the Pacific, and in Hawaii the female trees are the source of hala, one of the most important weaving materials in Polynesian culture. The fruit is edible in the better forms — the ripe segments are chewed for their sweet, fibrous flesh — but many wild trees are poor and the fruit of the genus needs cooking or selection to be worth the effort. On a coastline the prop-rooted trees bind dune sand and absorb wave energy, which is why they are protected along many tropical shores.
Growing from Seed
The hard stones germinate slowly but reliably if they are kept warm and moist; soak them for two days in tepid water first, then bury them just below the surface of a sandy mix at 25 to 30 °C. Germination can take two to six months, and there is no advantage in hurry. Alternatively, and much faster, take a sucker or a ripe cutting from a good fruiting tree — named cultivars are always propagated this way, because seedlings vary in fruit quality and sex. Grow the young plants in full sun, in a free-draining mix, and keep them potted until the trunk has begun to thicken. They are salt-tolerant and wind-tolerant but not frost-tolerant at all, and a single hard freeze will end the attempt.
Our Take
A coastal tree with a thousand uses and a shape unlike anything else, but it wants a tropical or near-tropical climate and space for the root cone.
Related Reading
More species in the same orbit as Screwpine: