IN THE ARBORETUM TODAY
by Alfredo Chiri

LONGAN - Dimocarpus longana - Sapindaceae
Donated by: CRFG/McIntyre and planted in 1980 (r.f.-08)
Common names: Dragon's eye, Li-chihnu, Mamoncillo chino

The longan is a native to southern China, growing there at elevations from 500 to 1500 feet. The longan tree is closely related to the lychee
(Litchi chinensis), even though they are botanically placed in a different genus. The longan tree thrives much better on higher ground than the lychee and accepts more frost.

The longan tree grows up to 30 feet in height and to 40 feet in width, the rough-barked trunk to 2 feet thick. The tree is erect with slightly
drooping foliaged branches. The evergreen leaves are lanceolate with a blunt tip, 4 to 8 inches long and about 2 inches wide. The upper surface of the leaf is a glossy green, while beneath it has minute hairs and is of a gray-green color. New growth has a burgundy color and is very showy.

The flowers are of a pale-yellow color with 5 to 6 petals, larger than those of the lychee. Flowers are borne in upright terminal panicles, male and female mingled. The fruits are globose, 1/2 to 1 inch in diameter, grown in clusters. The skin is thin with a yellowish-to-reddish brown color, with rough protuberances but much less prominent than those of the lychee. The flesh is white, translucent, sweet and not as flavored as the lychee.

The seed is round, jet-black, with a circular white spot at the base, giving it the aspect of an eye.

The longan thrives best on rich sandy loam or on soils that are moderately acid, somewhat organic. In organic muck soils the longan might
not bloom or fruit. With long periods of cool weather in the winter months but with no frost, longan trees bloom well. Blooming is poor after a warm winter.

Most longans are grown from seed. Seeds lose viability quickly. Germination takes place within a week. Seeds are planted 3/4 inch deep;
otherwise they may send up more than one sprout. Seedlings are transplanted to a shaded area the following spring and set in the field
2-3 years later during winter dormancy. Grafting is uncommon, and when it is done, longan rootstock is used. Also vegetative propagation is mostly by means of inarching onto 3-5 year old 'Wu Yuan' seedlings, that are characterized by their vigor as a longan rootstock.

The longan is relatively free of pests and diseases. Most of the problems can be related to signs of mineral deficiency, which can be corrected by supplying minor elements during the fertilization program. The longan tree needs an adequate supply of water and can stand brief flooding but not prolonged drought. Pruning is an important operation. Flowers are removed from the clusters, and fruits are removed from the clusters to improve the quality of the fruit.