Bombax ceiba Seeds | Red Silk Cotton Tree

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Red Silk Cotton Tree (Bombax ceiba) seed — Red Silk Cotton Tree (*Bombax ceiba*): Malvaceae, native to South and Southeast Asia, from Pakistan and India through Nepal, Bangladesh, Myanmar, Thailand and southern China to Malaysia and Indonesia, in the seasonal tropics below about 1,500 m.

LATIN NAME: Bombax ceiba

COMMON NAME: Red Silk Cotton Tree

Plant Profile

For a few weeks in the dry season the silk cotton tree stands entirely without leaves and entirely covered in flowers. The blooms are deep red and waxy, opening in clusters at the ends of bare branches, and from a distance the tree reads as a red tower above the budding green around it. Then the show ends, the petals drop, and only afterward does the new foliage expand.

The flowers pay for their pollinators with volume. Each bloom holds a well of dilute nectar behind a brush of stamens, and the visitors are the strong fliers: sunbirds and other nectar-feeding birds by day, and fruit bats in the warmer parts of the range. The tree is a conspicuous feeding station in a season when little else is in flower.

A young tree defends itself. The trunk carries conical woody spines while the plant is small and vulnerable, and they are usually lost as the tree matures. Old specimens develop buttresses at the base and a pale timber that is light and soft, and it has served for packing cases, matchboxes, plywood core and, in some districts, for carved canoes and drum shells.

In southern China and parts of Southeast Asia the fallen flowers are collected, dried and used in slow-cooked soups and teas, where they contribute a mild bitterness rather than aroma. The calyx and petals are separated from the stamens before drying. This is a domestic and regional use, not a pharmacy, and the tree also supplies a gum and a fibre that once supported small rural trades.

The species is a favourite municipal tree across South Asia and southern China because it is fast-growing and tolerant, and drought-resistant once established. The same qualities create a management task: when the capsules open, the floss blows through the streets, clogs grates and collects in air-conditioning intakes, and the seed beneath it encourages weeds wherever it settles. Cities sweep hard during the fruiting season.

Science & Biotechnology

Older floras placed the silk cottons in their own family, the Bombacaceae, with the baobabs and durians. Molecular work dissolved that family and moved its genera into an expanded Malvaceae, so the red silk cotton tree now sits in the same family as hibiscus, cotton and okra, in the subfamily Bombacoideae. The change reflects real shared anatomy, including the mucilage canals that link the old bombax group to the mallows.

The tree has a substantial phytochemical literature. The leaves contain the flavonoid shamimin, an unusual C-glycoside that has been investigated for its biological activity, and to this are added triterpenes such as lupeol and sterols including beta-sitosterol in bark and root, together with flavonoids such as quercetin and kaempferol in the flowers.

Uses & Benefits

The fruit is a leathery capsule that swells through the wet season and splits along its valves when ripe, releasing seed embedded in a mass of fine white floss. That fibre is harvested by gathering the capsules as they begin to open, drying them in the sun until the valves spring back, then separating the fibre and seed by hand or with a simple gin. The floss is short and slippery compared with cotton, so it is used for stuffing cushions, mattresses and upholstery padding.

Kapok fibre is remarkable at the microscopic scale. Each fibre is a thin-walled tube sealed at one end and filled with air. Those hollow tubes also trap oil, and researchers have used both raw and acetylated kapok fibre as a sorbent for oil spills, where the fibre floats and can be skimmed off the water surface. The floss of Bombax ceiba is shorter than the commercial Ceiba pentandra fibre, but the same physics applies.

Growing from Seed

Collect seed from freshly opened capsules and sow it promptly, because the floss needs no treatment and the kernel loses vigour in storage. Use a mix of two parts loam, one part coarse sand and one part compost, and sow about 1 cm deep in deep pots, since the young tree makes a strong, straight root from the start. Keep the medium warm and only just moist, and give full sun from the beginning.

Plant out at the start of the warm season, spacing garden specimens at least 8 m apart, and stake for the first two seasons only. Water deeply and less often to drive roots down, then reduce irrigation once the tree is established. Remove the lower branches while the stem is still young so that the trunk lifts into a clean column, and cut out water shoots that appear around pruning wounds.

Our Take

The red silk cotton tree is a statement plant with a working second life in fibre and gum. Give it a corner where the fruiting floss will not block a drain. For a white-flowered analogue grow the white silk cotton tree, and for a pink-floss relative in the same subfamily try the pink floss silk tree; the coastal sea hibiscus shows the malvaceous kinship in a smaller size.

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