In India, the neem tree seems to grow everywhere, its leaves providing welcome shade from the hot sun. All parts of the tree, however, have something to offer and have long been used to treat a range of ailments in ancient Indian medicine, known as Ayurveda. (The tree’s name in Sanskrit means "reliever of sickness.")
For centuries, the juice from neem leaves has been used to soothe skin disorders. Its twigs are chewed as cavity-preventing toothbrushes. In homes, neem leaves—which resemble those of the walnut tree—are used to keep bugs out of beds and stored food; and on the farm, they protect crops from pests, including locusts.
The book Neem: A Tree for Solving Global Problems (National Research Council, 1992) and 460 studies cited on the PubMed database describe neem’s many beneficial aspects: Various parts of the tree have anti-malarial, antiseptic, antibacterial, antifungal, anti-parasitic, anti-inflammatory and anti-ulcer properties. Caution is necessary, however, as neem oil and neem leaves also can be toxic. Because some research has shown that neem can prevent fertility, the plant should not be used by anyone—male or female—wishing to have a child.
In the United States, neem leaves are sold in capsules for internal purifying and cleansing. Neem oil from neem seeds should not to be ingested, but it can be applied topically to relieve dry, itchy skin. Added to creams, lotions, shampoos and soaps, its benefits are similar to tea tree oil. Like coconut oil, neem oil solidifies at room temperatures.
Neem also is appearing as the main ingredient in new organic and "bio-rational" pesticides. It works against insects by repelling them, preventing their feeding and disrupting their growth.
If you can grow a ficus outdoors, you can grow a neem tree, reports Neem Tree Farms in Bradenton, Florida. Only the warmest areas of Florida, Texas, Arizona and California (Zone 10) are warm enough to grow neem, however. The trees will grow quickly given rich, moist (but not wet) soil and full sun. In colder climates, try growing neem in a pot and bring it indoors for winter, like a houseplant. Unlike many houseplants, your naturally repellent neem probably won’t suffer from spider mites or scale.
Joanna Poncavage gardens and writes in Pennsylvania, where she can’t grow a ficus outdoors.