Things You'll Need
Iron chelate soil drench
The longan tree (Dimocarpus longan Lour. ) is related to lychee and rambutan. It is an evergreen tree with some species reaching 100 feet tall. Most cultivated varieties, though, will reach 30 to 40 feet, if left unpruned. Longan bears small, light brown fruit with white flesh in subtropical regions such as Florida. A drought-tolerant tree, it can, in fact, be harmed by overwatering or prolonged periods of rain. Like most fruit trees, the longan requires careful attention to fertilization; a consistent schedule is vital to the tree's success.
Grow the longan tree in full sun in the warmest, driest area of the garden.
Water the young longan tree regularly to keep the soil moist. When the tree begins bearing fruit, it only requires a regular irrigation schedule while it is in flower and bearing fruit. Withhold water in September and October.
Maintain a grass- and weed-free area around the trunk of the longan tree. Apply a 4-inch layer of mulch, 8 inches from the tree's trunk and spread out to the dripline. Mulch helps discourage weed growth.
Fertilize the first-year longan tree with 1/4 lb. of 6-6-6 fertilizer every eight weeks. Increase the amount of fertilizer to 1/2 lb. in the second year but decrease the frequency of applications to four, split evenly throughout the year. Follow this same schedule in the third year, increasing the amount of fertilizer to 1 lb. Mature longan trees require 5 lbs. of fertilizer just before the tree blooms in late spring and again before harvest. Spread the granular fertilizer on the soil beneath the tree, 5 inches from the trunk, and spread it out 1 foot beyond the dripline. Water well after applying.
Apply an iron chelate soil drench around the tree in July, according to the manufacturer's instructions. Reapply at the same rate in early September.
Inspect the longan tree periodically for pests. Contact your county cooperative extension service to find out approved control methods.
Prune the longan tree to keep it to a manageable size. Agriculturists with the University of Florida suggest that the tree be kept no taller than 15 feet high and 30 feet wide. Cutting 1 to 2 inches from the tips of new shoots on the young longan tree during the spring and summer will help keep the tree compact.