Dimocarpus longan (Sapindaceae)
English: longan, lungan, dragon eye
Spanish: longán, longana
French: longanier, oeil de dragon
Indonesia, Malaysia: leng-keng
Burma: kyet mouk
Laos: lam nhai, nam nhai
Thailand: lamyai pa
Origin and Distribution
Native to Southeast Asia. Cultivated throughout the tropics and subtropics, but primarily in Thailand, China, Taiwan, Vietnam, Australia, and in the USA, Florida and Hawaii.
Euphoria longana, Euphoria longan, Nephelium longana, Nephelium longan.
Large tree, to 50 feet (15 m) tall, with a dense, symmetrical crown and rough bark. Alternate, compound leaves to 12 inches (30 cm) in length, with 6-9 pairs of leaflets. Flowers staminate, pistillate and hermaphroditic, small, whitish, produced in terminal or axillary panicles. Fruits round, 0.5-1 inch (1-2.5 cm) in diameter, with a rough, light brown peel and a sweet, translucent, whitish pulp surrounding a smooth black seed.
Propagation and Culture
Longan may be propagated by seed, cuttings, air layers or grafting. The seeds lose viability quickly and should be kept moist or planted promptly. Air layering is the most common method of propagating the longan, but the resulting trees have weak root systems, and may be blown over in strong winds. Grafting methods used include cleft, side veneer and approach. Seedling trees can take 7 years or more to fruit, while grafted or air layered trees produce in 3-4 years or less.
Like the lychee, longan is adapted to a subtropical environment with warm, humid summers and cool, dry winters. Nevertheless, it doesn’t tolerate temperatures below 32F (0C), and temperatures of 26 to 28F (-2 to -3C) can cause severe damage or death to young trees. In the tropics, longan can be grown from sea level to 1,800 feet (549 m) altitude.
The longan is adaptable to different soils, but doesn’t tolerate waterlogging or saline conditions. Growth is best in fertile, deep soils with a pH of 5.5 to 6. Trees should be planted at a distance of 18-25 feet (5.5-7.6 m) apart. Regular applications of fertilizer and irrigation will promote rapid growth, but should be discontinued from September to March (in the Northern Hemisphere) to promote flowering. In the Northern Hemisphere, flowering occurs around March, and fruits ripen from July to September. A mature tree can produce from 50-500 pounds (23-227 kg) of fruit per year.
Flowering and fruiting are erratic in the longan, especially in the tropics. Flowering is thought to be induced by low temperatures and drought stress, but trees can be induced to flower by the application of a 1-2% potassium chlorate solution to the soil around the tree or to the foliage.
Cultivars and Related Species
Although there are numerous longan cultivars in Southeast Asia, the cultivar diversity is lower in other regions. The following cultivars are the most commonly cultivated in Puerto Rico, Florida and Hawaii:
‘Biew Kiew’ - From Thailand, with more consistent production in Hawaii than ‘Kohala’, but still requires cool winters to flower well. Good quality fruit, later than ‘Kohala’.
‘Diamond River’ (‘Phetsakon’) - A tropical longan from Thailand which has more reliable production in tropical areas. The fruit is of medium size, good quality and early.
‘Kohala’ - Originally from Hawaii, the most important cultivar in Florida, but has erratic production in tropical regions. The fruit is early, large, of good quality, and with a small seed.
‘Sri Chompoo’ - From Thailand, with more consistent fruiting in Hawaii than ‘Kohala’, but still requires cool winters to flower well. Large, good quality fruit.
Other cultivars include ‘Egami’, ‘E Wai’, ‘Edo’, ‘Edau’ and ‘Tiger Eye’.
Dimocarpus longan var. malesianus, the mata kuching, is a subspecies of longan that is better adapted to tropical conditions.
Longan fruit is consumed fresh, dried, frozen and canned.
Nutritional composition per 100 g longan fruit
Fresh fruit is consumed to reduce fevers, and the dried fruit as a cure for insomnia. Leaves contain quercetin, with antioxidant and antiviral properties, and are used in the treatment of allergies, cancer, diabetes and cardiovascular diseases. Crushed seeds produce foam, which is used as shampoo. The wood is used in the construction of furniture and other articles. The tree is also planted as an ornamental.
More information on longan
A Food and Agriculture Organization publication with a lot of current information on longan.
From the University of Florida, a good article with practical information for Florida and other subtropical regions.
From the 1987 classic by Julia Morton, “Fruits of Warm Climates”.
Information on longan production in California.
A brief article outlining longan production and management in Australia.
Summary of optimum conditions for storage of harvested longan fruit from the University of California.
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