The Neem Tree

Azadirachta indica

Also known as Mwarubaini (Swahili); Mkilifi (Giriama)

Family: Meliaceae (Mahogany family)

In Kenya, this tree is known as ‘Mwarubaini’ (from arobaini, the Swahili word for forty), because it is said to cure forty illnesses. People use the leaves, bark, roots and even the seeds of the Neem tree for medicine. And that is not all. The tree contains a chemical compound, Azadirachtin, which is a powerful insect repellent.

Neem trees provide medicine for the earth too! Farmers use neem cake (from the berries), leaves and twigs as mulch and green manure to improve the soil. Neem trees can survive in poor soil, and in dry areas, as their roots grow deep, reaching nutrients and water that other trees can’t get to. So, people plant them to improve degraded areas and to stabilise sand dunes. They are useful trees indeed!

The Neem tree originally came from South Asia. As it is highly valued there, the first seedlings were probably brought to Kenya by the people who sailed across the Indian Ocean, in dhows, hundreds of years ago. Today, the Neem tree has become naturalised in Kenya (that means it spreads and grows without being planted). You can see Neem trees everywhere on the coast, and they can be found in the Northern and Eastern lowlands, up to 1500 m above sea level.

Nairobi is too high for the Neem tree to grow. But its cousin, Melia azedarech, known as Mwarubaini nusu (half Mwarubaini) grows in our capital city. It shares many of the Neem trees' useful properties.

In his book ‘The Secret Life of Trees’, Colin Tudge says “There are many outstanding chemists among plants, but the neem is among the greatest of all. For centuries, indeed for thousands of years, the Indians have treasured the neem for medicines: it features in some of the most ancient Hindu texts. Many Hindus begin the new year by chewing neem leaves. Many clean their teeth with neem twigs. They treat skin disorders with its juice, and drink infusions as a tonic. Gum from the bark is used for dye. Neem has also proved active against more than 200 species of insects, preventing them from feeding, inhibiting their reproduction – discouraging egg-laying and disrupting the development of any eggs that are laid. As if to make the point a plague of locusts in India in 1959 destroyed just about everything that grew except the neems. The timber is termite-proof, and perfect therefore for hot climates, for anything from furniture to tool handles. Indians put the leaves in cupboards, to safeguard the contents. The leaves also make good fodder, while the seed are 45 percent oil and provide excellent seed cake for livestock, or oil for lamps. Very properly, the neem is venerated. Many Indian place names incorporate its name: Neemuch, Neemrana, Nemawar and hundreds more. The neem is said to have been blessed with nectar, sent from heaven.

Science has reinforced the folk law. Different parts of the neem, but particularly the seeds, contain a host of potent organic compounds shown to be active against just about everything pestilential: bacteria, fungi, viruses, nematodes and mites, as well as insects. A powerful spermicide is there too, raising hopes in some circles of an effective male contraceptive. Yet the extracts do not seem to harm mammals (including people) or birds. Outstanding amongst the compounds studied so far is azadirachtin. It is now being incorporated into commercial pesticides not only because it seems innately effective but also as part of a general swing away from industrial chemistry to biotech, based on natural processes and materials. Tudge, C., The Secret Life of Trees, p 222 - 223

Here are some of the things people use the Neem tree for...

Agroforestry (improves the soil)

Animal feed (Seed cake made from residue from oil press, leaves used as fodder)

Bee forage

Carving

Charcoal

Dye (made from resin )

Fertiliser

Firewood

Food (Shoots and flowers eaten as a vegetable in India)

Fuel (Oil from seeds used as paraffin substitute)

Fungicide

Furniture (termite resistant)

Insecticide (protects against more than 200 species of insects)

Medicine

Ornamental

Poles

Shade

Shampoo to

treat dandruff

Skin cream.

Soap

Toothbrushes (twigs contain antiseptic ingredients)

Toothpaste

Utensils (pestels and mortars)

Veterinary medicine

Windbreak

Do you know any more things Neem trees are used for? Let us know and we'll add them here.

To find out more about the Neem tree and how it is used visit the World Agroforestry website.

A warning!

Though the Neem tree is very useful to humans, it can be a threat to our native trees and forests. The CABI invasive species compendium notes that, though it does not possess the attributes of other invasive species (seeds that last a long time, competing with other plants at the seedling stage), it does produce a prolific number of seeds which are spread widely by the birds and animals that eat them.

Sources

Noad, T., Birnie, A. – Trees of Kenya

Dharani, N. – Field guide to common Trees and Shrubs of East Africa

Maundu, P. and Tengnas, B. (eds) Useful trees and shrubs for Kenya

Tudge, C. 2006 The Secret life of Trees