A gargantuan tropical deciduous tree, the cotton tree (Ceiba pentandra) flowers in late winter that later yield seed pods flush with seeds and beige cottony fibers. Also called the giant kapok, silk-cotton tree or lupuna, it makes a grand summer shade tree with many ornamental qualities. It grows in warm climates, in U.S. Department of Agriculture hardiness zones 9b and warmer.
Botanically known as Ceiba pentandra, older but now defunct synonyms include Bombax pentandrum, Ceiba caribeae and Ceiba casearia, according to the author of "Tropical Flowering Plants." Traditionally, it is regarded as a member of the kapok family, Bombacaceae, but modern taxonomists tend to lump it into the larger hibiscus family, Malvaceae.
Cotton tree is native to both tropical America and western Africa, being the tallest tree species on either continent according to "Tropical and Subtropical Trees" and TropiLab. In the New World the native range extends from southern Mexico to the Amazon Basin across Bolivia, Peru and Brazil. This tree is grown widespread across the tropics, so its nativity in Africa is muddy as it was grown as a crop tree. Some suggest the buoyant seeds traveled to Africa on the ocean winds from the Amazon.
One of the pioneer trees of the tropical rainforest, cotton tree quickly grows upward with a straight trunk with or without thorns on it. The branches radiate out in tiered whorls. Mature trees reach heights of 100 to 200 feet and 50 to 90 feet wide with a wide, buttressing trunk flare. In late winter as the tropical dry season nears its end, clusters of waxy pale yellow to ivory flowers with golden stamens don branch tips. The five-petaled flowers smell like milk and open at night, attracting bats for pollination. The green, hand-like leaves then emerge in midspring on long petiole stems, comprising five to eight leaflets. The flowers develop into pendent green seed pods that are boat-shaped and turn yellowish brown at maturity. The velvety pods split open to release hundreds of small brown seeds attached to long, silky hairs--the cotton. Leaves drop away in late fall when rainfall wanes, revealing the architecturally massive and interesting structure.
The silky cotton fibers, the "kapok," traditionally were used to fill pillows, cushions and mattresses and, according to "Tropical and Subtropical Trees," were used in Europe during World War II for padding and providing buoyancy for lifesaving jackets. The seeds are rich in oil and protein that is both edible and useful for soap and lighting. Debris from seed pressing is used as livestock feed. The wood of this tree is light and not good for lumber, perhaps a reason it was not heavily harvested from tropical forests and old plantations. Native South Americans did use hollowed-out logs for canoes. Today, the cotton tree makes an impressive ornamental tree for subtropical regions in parks and large gardens as well as just inland from the ocean.
Cotton tree is among the first trees to revegetate a rainforest clearing, quickly towering upward and providing shade and cover for other plant and animal life. Epiphytic plants like ferns, orchids and bromeliads clasp to the branches and trunks of trees leading to subsequent habitat for insects, snakes, frogs, birds and mammals like monkeys. Flowering and fruiting is heaviest in drier subtropical areas, so in true tropical rainy lands, the flowers may occur as infrequently as every four to five years, diminishing the nectar available to bats and ground-dwelling rodents once the flower petals drop. Abandoned plantations of cotton trees perpetuate a forest ecosystem.