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Bombax ceiba L. 1753
pronounced: BOM-baks SAY-buh
(Malvaceae – the hibiscus family)
Common names: Bombax, Red Silk Cotton Tree, Cotton Tree
This large deciduous tree is native to Cape York Peninsula and tropical Asia. It is a lowland tree found in several coastal habitats: in coastal vine thickets, on dunes or on cliffs above the beach, or around lowland streams. It is cultivated in the West Indies and Brazil. This tree has a tall, straight trunk, often buttressed. The trunk and branches bear numerous conical spines, particularly when young. The leaves are palmate, with about 6 leaflets radiating from a central point. In spring the tree is covered in large cup-shaped red flowers up to 20 cm in diameter, and these are filled with copious nectar. The numerous stamens have red filaments and are tipped with black anthers. The fruit is a brown capsule up to 1.5 cm long, filled with numerous black seeds covered in fine silky hairs, embedded in a cottony mass. New leaves usually do not appear until the flowering is over. Although each flower lasts only for a day, Bombax flowers are very popular with many birds, who get drunk on the fermenting nectar.
The seed floss’s individual fibres, soft and ranging in colour from pale yellow to brown, are about 5 mm to 3.25 cm long. Unlike the fibres of commercial cotton, Bombax fibres come from hairs that grow from the side of the seed-pod instead of from the seed itself. Although sometimes mixed with cotton fibres for spinning, it is a weaker fibre, and less elastic; it also contains the substance lignin, making it unsuitable for use alone as a textile fibre. It is mostly used for wadding and upholstery stuffing.
The tree is widely planted in Malaysia, Indonesia, south China, Hong Kong and Taiwan. In India it is very often seen planted in parks and on roadsides, because of its beautiful flowers. In China, the flower is used as an ingredient in herbal tea.
Before Bombax ceiba flowers, it drops all its leaves. There follows a spectacular array of glorious flowers at the tips of the bare branches. This is when the birds are attracted, and they pollinate the flowers while they are feeding on the nectar. The spent flowers carpet the ground under the tree. This spectacle lasts for about a month. As the fruits ripen and begin to dehisce, white cottony strands of fibre are released and float downwards, settling on the ground, on houses, and on whatever else is in their way.
The tree does not begin to releaf until almost all of the flowers have fallen; but, even without its flowers, this is still an impressive tree: giant in size (up to 30 m or more in height), it displays stout, prickly branches arranged in horizontal tiers emanating from the trunk.
Propagation is from seed, from large cuttings, or from layering.
Together with the other members of the subfamily Bombacoideae, the Bombax produces usable timber. The heartwood is pink-brown to deep red-brown; the sapwood is lighter coloured, and distinct in most species. The grain varies between species from straight to interlocked, the texture being coarse, and often uneven. The timbers are not particularly durable, the sapwood is susceptible to lyctid borer attack, and the wood is not resistant to termites. The timber seasons rapidly, but has a tendency to cup. The wood is described as ‘firm’ rather than ‘hard’; it machines well, but turning produces a slightly rough surface. It nails and glues well, and the seasoned timber readily accepts paint, stain and polish. Uses for the timber include light construction, plywood, furniture making, joinery and veneer. It is also used to make clogs. The timber has an unpleasant odour when freshly sawn.
As far as I know, there is no mature bombax tree on the island, so I have shown one of a pair of magnificent specimens in the Queen's Gardens, Townsville.
Photographs taken in Picnic Bay 2009, 2013 and in Townsville 2012
Page last updated 2nd December 2017