Azadirachta indica aka Neem

Azadirachta indica is the neem tree. People also call it margosa. It belongs to the Meliaceae family and grows fast. Kew gives its native range as Assam to Indo-China. Other sources give a wider range in tropical Asia. Neem grows in mixed woods. It also grows in lowland forests that stay green. People have planted it throughout the tropics and subtropics. Its dense crown shades hot, dry places.

Garden trees reach about 50–75 feet [15–23 metres] tall. Some reach 100 feet [30.5 metres]. Sources also report smaller heights. The crown can spread to 75 feet [22.9 metres]. Long branches form a broad crown, rounded or oval. The straight trunk has thick, dark grey bark. Old bark forms deep cracks and flakes off. This shows a reddish layer beneath it. Neem keeps its leaves unless a long drought makes them fall. Its pinnate leaves have green leaflets with toothed edges. Each leaflet has uneven sides. Some also have lobes.

Small white flowers hang in groups and smell sweet. Missouri Botanical Garden reports blooms in spring. It also lists flowering as seasonal. Each tree has both male and bisexual flowers. Bees and other insects help pollinate the flowers. Useful Tropical Plants says neem is not self-fertile. Its fruit is a drupe and looks like an olive. Most fruit has one seed. As fruit ripens, colours include yellow, brown and purple. Oregon State gives the time from bloom to ripe fruit. It reports about twelve weeks.

Neem grows best in warm tropical or subtropical sites. Missouri Botanical Garden lists USDA zones 10–12. It reports that neem fares poorly below 40°F [4.4°C]. Give it full sun or some shade. Deep, sandy soil suits it well if water drains freely. Once trees take root, they can cope with drought. Their soil can be dry to somewhat moist. Trees in pots cope less well with drought than outdoor trees. Prune indoor plants in pots to keep their size down. Sources report no major problems with pests or disease. Yet trees can grow from their own fallen seeds. They can spread beyond gardens. Neem has spread from planted sites in several tropical regions.

People use neem for shade and to block wind. They also use it to control dunes. It supplies wood, fuel and things used to make soap. It also supplies products that kill insects. Its seeds and leaves yield the insecticide azadirachtin. Neem has a long history in Ayurvedic medicine. People eat young leaves, flowers and fully ripe fruit pulp. Leaves and flowers taste bitter. Cooking changes how people use them. People make fermented drinks from sap. They also cook with refined seed oil. These food uses do not make all parts safe. Compounds in fruit and bark may cause vomiting. Neem extracts can harm fish and other life in water. They can also harm helpful insects.