Red Silk-Cotton Tree

Bombax ceiba is native to tropical and subtropical Asia, ranging from India and Sri Lanka through Southeast Asia to southern China and northern Australia.

• Found naturally in tropical moist deciduous and semi-evergreen forests across India, Bangladesh, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, Indonesia, and southern China
• Also occurs in northern Australia (Queensland)
• Occurs at elevations from sea level to approximately 1,500 meters
• Has been introduced to and naturalized in parts of tropical Africa, the Caribbean, and Central America
• Cultivated for millennia across tropical Asia for its fiber, timber, and ornamental value
• The tree is deeply embedded in the mythology and folklore of South and Southeast Asia
• In Hindu tradition, the Red Silk-Cotton Tree is associated with the god Indra and is sometimes called "Indra's Tree"
• First described scientifically by Carl Linnaeus in 1753
• The word "kapok" derives from the Malay "kêpok," referring to the silky fiber
• The fiber was commercially important from the late 19th century through the mid-20th century, before being largely replaced by synthetic fibers

Bombax ceiba is a large, briefly deciduous tree with a massive, buttressed trunk and spectacular floral display.

Size and habit:
• One of the tallest trees in tropical Asian forests, typically growing 20 to 40 meters tall
• Trunk is massive, 1 to 3 meters in diameter, with prominent buttress roots at the base
• Young trunks and branches are armed with large, conical, sharp thorns 1 to 3 cm long — a distinctive feature that disappears on older trunk surfaces
• Crown is large, spreading, and branchless for much of the trunk height in forest specimens
• Bark is grayish, smooth on young trees, becoming rough and fissured with age

Leaves:
• Large, palmately compound, with 5 to 7 (sometimes up to 9) narrow, lanceolate leaflets
• Leaflets are 10 to 20 cm long and 2 to 4 cm wide, dark green above, paler below
• Leaves drop during the dry season, leaving the tree bare for several weeks before flowering

Flowers:
• Among the most spectacular tree flowers in tropical Asia — large, 10 to 15 cm in diameter
• Brilliant crimson to deep red, sometimes orange-red, with five thick, fleshy petals
• Numerous long, dark red stamens create a dramatic, firework-like center
• Flowers appear in late winter to early spring on leafless branches, covering the tree in a blaze of red
• Flowers are pollinated by birds (especially sunbirds and bulbuls) and bats

Fruit:
• Large, ovoid to ellipsoidal capsules, 10 to 20 cm long
• Capsules split open when mature to reveal masses of silky white kapok fiber surrounding small black seeds
• The fiber is extremely light, buoyant, and water-resistant — adapted for wind dispersal
• Each seed is embedded in its own tuft of silk-cotton fiber

Bombax ceiba plays a significant ecological role in tropical Asian forests.

Habitat:
• Tropical moist deciduous and semi-evergreen forests, often in valley bottoms and along streams
• Also found in seasonally dry forests and monsoon forests
• Occurs from sea level to 1,500 meters
• Often emerges above the forest canopy as one of the tallest trees in the landscape

Ecological role:
• Flowers are a critical nectar source for sunbirds, bulbuls, bats, and other pollinators during the late dry season when few other trees are flowering
• Kapok fiber provides nesting material for birds and is used by some species to line their nests
• Seeds are eaten by birds and small mammals
• The massive, buttressed trunk provides shelter and habitat for cavity-nesting birds and roosting bats
• Trunk thorns on young trees deter climbing animals from reaching the crown
• Emergent trees provide important perching and nesting sites for large raptors
• Leaf litter enriches forest floor nutrients
• Deep root systems stabilize soil along streambanks
• Old trees develop hollows that serve as dens for arboreal mammals

Planting:
• Propagation from seed or cuttings
• Seeds are embedded in kapok fiber — remove fiber and sow fresh seeds immediately
• Germination occurs in 1 to 3 weeks
• Large branch cuttings (truncheons) root readily when planted during the rainy season
• Fast-growing, reaching 3 to 5 meters in the first few years
• Plant in full sun in deep, well-drained, fertile soil
• Adaptable to a range of soil types
• Hardy in USDA zones 10 to 12
• Requires a distinct dry season for best flowering
• Water regularly during establishment; drought-tolerant once mature
• Prune young trees to develop a strong structure
• Space at least 10 to 15 meters from buildings and infrastructure — the massive mature size requires ample room
• Not suitable for small gardens
• Often self-seeds in suitable tropical habitats
• Thorns on young trees can be a hazard — plant away from walkways
• Excellent specimen tree for large parks and botanical gardens

Uses:
• Kapok fiber was historically the premier filling for mattresses, pillows, upholstery, and life jackets — it is 8 times lighter than cotton and naturally buoyant
• The fiber is still used in traditional pillow and mattress making in parts of South and Southeast Asia
• Wood is soft, lightweight, and easy to work — used for making matchsticks, coffins, surfboards, and model airplanes
• Young flowers are eaten as a vegetable in some Southeast Asian cuisines
• Flower buds are pickled in parts of India
• Roots are used in traditional Chinese and Ayurvedic medicine for various ailments
• Bark is used in traditional medicine as an astringent and to treat diarrhea
• Gum from the bark is used as a food additive and in traditional medicine
• Seeds yield a pale yellow oil used for illumination and soap-making
• Widely planted as an ornamental and shade tree in parks, along roads, and in temple grounds across tropical Asia
• Wood pulp is used for paper-making
• The tree is sacred in many Asian cultures and is often planted near temples and shrines
• In Bengali culture, the Shimul flower is a symbol of spring and is celebrated in literature and song
• Leaves are used as fodder for livestock