How to Grow A Longan Tree

The longan tree (Dimocarpus longan, lungan) is a tropical fruit tree that is believed to have originated in the area between India and Burma or in China. In India it is known as Pichu पीचू. It is now grown in many parts of the World for longan fruit benefits. The tree, like a lychee tree, is an evergreen tree which reaches a height of more than 15 feet. It will reach to a smaller height if grown in a container.



Longan Tree Care and Growing Information

Learn how to care and grow a Dimocarpus longan as regards to its planting position, soil requirement, its watering needs, fertilization, pests and diseases and tips for pruning of the tree and harvesting the fruits.

Planting a Longan Tree


A Mature Longan Tree
A Mature Longan Tree
The longan trees have mostly been grown from seed.
  1. The seeds should be dried in shade for shade for 4 day, they should immediately be planted, otherwise they lose their viability quickly. 
  2. Sow the seed about 3/4 inch (2 cm) deep.
  3. If you sow the seed more deeper,  more than one sprout may occur. 
  4. Germination takes place in 7- 10 days. 
  5. Transplant the seedling in a shaded place in the following spring.
  6. Plant the seedling after 2-3 years in the final position during winter dormancy.

Position

  1. Select the driest and hottest area of the garden, which does not remain wet for long time.
  2. The tree is not tolerant to excessively wet or flooded soil conditions and it may die due to constantly wet soil conditions.
  3. Plant the longan tree quite away from the lawn because the roots of the mature tree spread beyond the drip-line and heavy lawn fertilization may reduce fruiting and or fruit quality.
  4. Plant away from the lawn as the lawn mower if accidentally damages the trunk of the tree can reduce fruiting or even the tree may die.

Soil

  1. Longan tree can grow on well drained various soil types including sand, sandy loams, calcareous and rocky soils.
  2. Keep the area around the trunk of the longan tree free from grass and weed.
  3. Apply a 10 cm (4 inch) layer of bark, wood chips or similar mulch material spreading to the drip-line from 12 inch of the trunk. It will protect the trunk from rot and suppress weeds and hold soil moisture.

Watering

  1. Keep the soil of the young tree moist. When the tree starts to produce flowers, water regularly till it bears fruit.
  2. Excessive rains during flowering may cause flower drop and reduce pollination.
  3. Established trees should be irrigated regularly from the signs of blooming appear and until harvest.
  4. The use of sprinklers on a timer may result in over watering, causing root rot and decline.
  5. Warm and rainy winters encourage vegetative growth and reduce flowering.

Fertilization

During the immature stage, a combination of organic and inorganic fertilizers may be used. Organic fertilizer such as cow manure can be applied at the rate of about 10 kg/tree/year, applied about 3-4 times in a year.
  1. The longan tree requires equal ratio N:P:K fertilizer (i.e. 6:6:6 or 15:15:15, etc.). Spread the fertilizer on the soil, 10 inches from the trunk, and spread it out 1 foot beyond the drip-line. Water well after applying.
  2. First year of planting: After one month of planting, fertilize with about 110 g (1/4 pound) of 5-5-5 NPK fertilizer every 2 months.
  3. Second Year: Fertilize with about 220 g (1/2 pound) every 3 months.
  4. Third year: Fertilize with about 450 g (1 pound) every 3 months.
  5. Mature Trees: Mature longan trees require 1.5 to 2.25 kg (3.3 - 5 pound) of fertilizer just before the tree blooms in late spring and again before or during the harvest.
  6. If the soil is acid to neutral, apply iron sulfate at 5 to 30 g per tree to the soil 3 to 4 times a year.
  7. If the soil is alkaline soil, mix 14-20 g of iron chelate with 14-20 liter of water and pour on to the soil around tree trunk during winter.&
  8. Do not fertilize your longan tree during the winter, specially nitrogen containing fertilizer as this will encourage growth during the winter and reduce flowering in the spring. 
  9. Sprays 4-6 liquid feeds containing magnesium, manganese, zinc, molybdenum and boron during the warm part of the year.
In Australia, for a high yielding five year old longan tree, fertilizer (NPK 4:1:5, exactly 625 g N, 150 g P and 800 g K) has been been recommended to be applied four times during the following crop cycle:

1. panicle emergence,
2. one month before fruit set in September to October,
3. one month after fruit set in December to January
4. two weeks after harvest in March to April.

The above fertilizer can be increased by 20 to 30 percent per year to 1,250 g N, 300 g P and 1,600 g K at year ten.

Thinning and Fruit Size
Removing about half of the fruit when they are of pea size in the early spring will result in larger fruit size. Panicles with 150 or more fruit usually produce smaller fruit so cut half of each panicle in the early spring.

Pruning of Longan Tree

A Young Longan Tree
This 5-7 year old Longan Tree
The picture shows a 5-7 year old Longan tree which is not growing properly as its roots are competing with lawn and other plants. It has not been properly pruned to make it dense.
  1. You can prune the longan tree after harvest to control its height and spread. Trees more than about 10 to 15 ft high (3 - 4.5m) and 15 to 30 ft (4.5 - 9 m) wide are difficult to care.
  2. 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.
  3. Bend long upright branches to a horizontal position by tying to keep the tree at a lower height.
  4. Pruning longan tree in winter will reduce flowering in the spring.
  5. For immature tree, only limited numbers of main branches are retained to obtain the desired structure. In China, one strong branch is retained after every growth flush to form a natural round-shaped crown of 6 to 10 main branches.

Pruning of Mature Trees

A mature tree can be pruned during and immediately after fruit harvest to control its size, making a lower tree canopy. If the tree becomes too dense, removal of some branches will increase air circulation.

The branches that are dead or infested by pests and diseases should also be removed. Weak branches, which have lost their vitality, are also pruned.

Insects and Pests

The most common pests on the longan tree are the lychee webworm and several scale insects. The lychee webworm attacks emerging shoots and panicles, flowers and young fruit and if left uncontrolled drastically reduce fruit set and crop yields.

Scales insects like banana shaped (Coccus acutissimus) and barnacle (Ceroplastes spp.) are other common pests that attack the tree, mostly the underside of leaves and the philephedra scale (Phillephedra tuberculosa) attacks leaves and fruit.

Bats or flying foxes can eat up longan fruits during fruiting seasons. A protective net around the perimeter of the tree can be erected.

Diseases

  1. The longan tree is free from major disease problems.
  2. During high humidity, warm and rainy weather, the limbs, bark and leaves are attacked by Red alga (Cephaleuros virescens), which produce dark gray to reddish-rust colored spots and patches.
  3. In severe infections, leaf drop and stem die back occur.
  4. Parasitic lichen (Strigula sp.) may produce white star-shaped spots on leaves which reduces their photosynthesis ability.

When Longan Tree Will Bear Fruit

Generally, the longan tree does not bear fruits every year and it may produce no fruit or little fruit.

Fruits grown from seeds may take up to 7 years to bear fruit. The longan tree propagated from air layering method may bear fruit 2-3 years after planting.

Harvesting Longan Fruits

  1. The longan trees do not bear fruit every year.
  2. The fruits can be protected from birds by netting or bagging the fruit in paper bags.
  3. The longan fruit do not continue to ripen after they are removed from tree unlike bananas, guavas and mangoes. So you should be sure that the fruits have ripen before you pick them.
  4. Wait for the fruits to change their colour to light brown and size 2 cm or greater with good flavour. 
  5. You may pick one fruit and taste for its sweetness before you harvest them.
  6. Caution: During the harvest, too much removal of leaves and wood with the fruit panicles can reduce flowering the next season.
  7. You can refrigerate the fruits in plastic bags for later use.

References
1. Longan Growing in the Florida Home Landscape, Jonathan H. Crane, Carlos F. Balerdi, Steven A. Sargent and Ian Maguire, Fact Sheet HS-49, https://edis.ifas.ufl.edu/mg049
2. Longan production in Asia, Wong Kai Choo, ftp://ftp.fao.org/docrep/fao/003/x6908e/x6908e00.pdf (part1), ftp://ftp.fao.org/docrep/fao/003/x6908e/x6908e01.pdf (part2)
3. Menzel, C.M., Watson, B.J. and Simpson, D.R., Longan.
In : T.K. Bose and S.K. Mitra (eds.) Fruits: Tropical and Subtropical. Naya Prokash, Calcutta, India, 522-546 (1990)
4. Longan, Morton, J., 259–262. In: Fruits of warm climates. Julia F. Morton, Miami, FL. (1987)

5comments

Thanks for the tips. The location of the tree seems to be important since it is intolerable to excessive moisture and water. Good post.
Reply

I have moved to a new house where a longan tree is growing in a low lying area. I fear that during rain, the water from the whole house will fill this area. Should I move this longan plant?
Reply

The longan tree thrives on a place which is dry and hot. So it is a good idea to transfer the plant to a drier location if the tree is still young and small. If the tree is already matured, then divert the flow of water away from the tree.
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