Dillenia is a genus of trees and shrubs native to southern Asia, the Pacific Islands, and Australia. One species, D. indica or the elephant apple, is cultivated for its edible fruit in regions like India. Some species are grown ornamentally in gardens in tropical and subtropical regions of the world, in addition to greenhouses. Nurseries sometimes carry Dillenia species or can order them by arrangement. Gardeners can also propagate from seeds or cuttings if they know people with established plants in their gardens.
These plants produce simple leaves arrayed in a spiral arrangement around the branches. The flowers appear terminally, at the end of the branches, in the form of single blooms or small racemes. They vary in color and size; D. indica produces distinctive very large bright yellow flowers. Many species have scented flowers and the odor is sometimes compared to lemons or onions, depending on the species. They are evergreen to deciduous in various parts of their natural range.
The fruit of the elephant apple tree is large, green, and knobbly. It can be used in the production of numerous fruit dishes and is also used in the preparation of traditional medicines. The fruit has a distinctive lemony flavor and may be eaten out of hand, as well as being used to make jams, jellies, and other foods. The fruits can also be used for seeds to grow new plants.
Gardeners interested in cultivating Dillenia will need to live in United States Department of Agriculture (USDA) zones nine through 11 or must have access to a greenhouse. These plants prefer full sun to part shade and rich, well-drained soil, as well as a humid environment, if possible. Preparing the soil well before establishing a seedling is recommended to give the Dillenia tree a strong and healthy start, and gardeners should also fertilize regularly to promote even, healthy development.
Commercial plantations are used to produce fruits for sale. In regions where these plants cannot be grown, it may be possible to obtain fruits through greengrocers and specialty fruit shops. The fruit is relatively stable and ships well, making it an excellent candidate for transport to other regions of the world. People can also purchase foods made with Dillenia fruits, ranging from chutneys for serving alongside spicy dishes to jams for spreading on toasts and using in desserts. Asian grocers can be a good source for these food items, particularly if they specialize in South Asian cuisine.