Thanks for submitting this article goes to Bryan Brunner of Montoso Gardens
The rambutan (Nephelium lappaceum) is a tropical fruit that is relatively unknown in the Western Hemisphere. It belongs to the Sapindaceae, a family of around 1,500 species of trees, shrubs and vines. Originally from Malaysia and Indonesia, rambutan is now cultivated throughout the tropics. Commercial production is primarily concentrated in Thailand, Malaysia, Indonesia, Philippines, Australia, Sri Lanka, Vietnam, Honduras and Hawaii. There are over 30 species of Nephelium with edible fruits. Other species include pulasan (N. ramboutan-ake), korlan (N. hypoleucum), giant rambutan (N. cuspidatum), sungkit (N. maingayi) and arut (N. xerospermoides).
Rambutan trees can be large, to 80 feet (24 m) in the wild, but usually do not grow to more than 45 feet (14 m) in cultivation. The leaves are alternate and compound, about 8-12 inches (20-31 cm) in length, the leaflets are dull green. The flowers are small and without petals, perfect but functionally staminate or pistillate, in axillary or terminal panicles. Fruits are round to ovoid, 2-3 inches (5-8 cm) long, with a red, orange or yellow peel covered with hairlike spinterns. The pulp is white, translucent, aromatic and sweet, and surrounds a seed which resembles an almond.
Rambutan may be propagated by seed, grafting or air layers. The seed loses viability quickly, and must not be allowed to dry out before planting. Germination occurs in 10-14 days. Young trees benefit from approximately 50% shade, but can take full sun once they are established in the field. Grafting is the most common method of propagation. Approach grafting and patch budding are both used successfully.
The rambutan is adapted to the wet, humid tropics, and grows well in acid, well drained soils with a high organic matter content from sea level to about 1,800 feet (550 m) elevation. The rainfall should be fairly well distributed throughout the year, although a short dry season is tolerated and may induce flowering. Temperatures below 41F (5C) can cause defoliation and death of trees.
Rambutans respond well to high soil fertility, and should be fertilized regularly during the growing season. Grafted trees begin to produce at 3-4 years of age, and a mature tree can produce over 200 pounds (91 kg) of fruit per year. In the Northern Hemisphere, flowering occurs principally between February and April, with a second flowering sometimes occurring in August and September. Fruit matures from July to October, and from November through January for the second harvest.
Rambutan fruit is consumed fresh, as well as canned and processed into jams. The fruit contains the following nutritional composition per 100 g of fruit: 14-14.5 g carbohydrate, 0.1 g fat, 0.7-0.9 g protein, 22 mg calcium, 30 mg phosphorous, 140 mg potassium, 2.5 mg iron, 0.01-0.1 mg niacin, and 31-38.6 mg vitamin C. A root extract is used to treat fever, and a bark extract for tongue diseases. A poultice of crushed leaves is placed on the head to relieve headache.
Bryan Brunner
Botanical garden and online nursery specializing in exotic tropical fruits, heliconias, gingers, palms, bromeliads and other rare plants.
