Boab trees, also known as baobab, upside down, bottle and monkey bread trees, are believed to be the largest succulents in the world as well as some of the tallest trees. There are several different species that vary somewhat in appearance, but all are deciduous, flowering trees that can can live for hundreds and even thousands of years.
Boabs are slow-growing trees that are indigenous to Madagascar, Africa and Australia. They can grow up to 70 feet tall and feature an over-sized, extremely wide caudex that the plant utilizes for water storage during the dry season. The bark is brown and gray and typically smooth, though it can crack and bend as the tree ages. Leaves are elongated and appear in clusters of up to seven leaflets. During the winter the plant sheds its leaves only to regrow them in the springtime and summer.
In the wild, animals such as baboons and elephants feed on the fallen fruit of the boab and disperse the seeds. In captivity, boabs are propagated by seed as well. The bean-sized, dark boab seeds must be carefully removed from the fruit and the chalky residue washed off. After soaking the seeds in water for at least 24 hours they can be planted in seed-starting trays with good quality potting mix infused with a small percentage of sand to ensure good drainage. When placed in partial shade, the seeds should germinate within six weeks. Once the boabs are 1 or 2 inches tall they can be transplanted into their own containers, fertilized and placed in full sun. Because they are not frost tolerant nor can they tolerate cold, they must be kept in heated greenhouses in most locales, most commonly as potted bonsai specimens.
Pollination and Flowers
The grandiose, fragrant flowers of the boab tree hang from droopy stalks in the late autumn once a tree is about 20 years old. The night-blooming blossoms have a sweet-smelling nectar that summons fruit bats which fertilize the flowers. Within a day of pollination the flowers drop off the tree. They are ultimately replaced by oval-shaped fruit with a hard, brown outer shell.
Boab trees have many purposes within the animal kingdom. African bees often make nests deep in the fibrous trunks of the trees. Various species of birds and insects nest on the branches and in the body of the tree. Elephants and buffalo chew on the moisture-laden bark to stay hydrated, especially during drought. Many farmers will feed their cattle and other livestock pieces of the wood as well as the seeds for the same reasons.
Humans make good use of boab trees by utilizing the bark to weave fabric for everyday items such as clothing and rope. Pulp from the fruit can be made into a sweet drink believed to relieve certain illnesses such as diarrhea. Young boab leaves contain vitamins and can be eaten.In certain indigenous cultures, people eat the caterpillars that feed on the boab leaves, as they are high in protein and nutrition.