The longan tree is a tropical fruit tree that is believed to have originated in the area between Asia. The tree, like a lychee tree, is an evergreen tree which reaches a height of more than 15 – 16 feet. It will reach to a smaller height if grown in a container.
Longan Tree Growing and Care Information
Learn how to care and grow a Dimocarpus longan as regards to its planting position, soil requirement, fertilization, watering needs, pest and diseases and tips for pruning of the tree and harvesting the fruits.
Planting a Longan Tree
The longan tree haves have mostly been grown from seed.
- The seeds should be dried in shade for shade for 4 until 5 day, they should immediately be planted, otherwise they lose their viability quickly;
- Show the seed about 3/4 inch (2 cm) deep;
- If you sow the seed more deeper, more than one sprout may occur;
- Germination takes place in 6 – 10 days;
- Transplant the seedling in a shaded place in the following spring;
- Plant the seedling after 2 – 3 years in the final position during winter dormancy.
- Select the driest and hottest area of the garden, which doesn’t remain wet for long time;
- The trees in not tolerant to excessively wet or flooded soil conditions and it may die due to constantly wet soil conditions;
- 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;
- 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.
- Longan tree can grow on well drained various soil types including sand, calcareous, rocky soils, and sandy loams;
- Keep the area around the trunk of the longan tree free from weed and grass;
- Apply a 10 cm (4 inch) layer of bark, wood chips 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.
- Keep the soil of the young tree moist. When the tree starts to produce flowers, water regularly till it bears fruit;
- Excessive rains during flowering may cause flower drop and reduce pollination;
- Established trees should be irrigated regularly from the signs of blooming appear and until harvest fruit;
- The use of sprinklers on a timer may result in over watering, causing root rot and decline;
- Warm and rainy winters encourage vegetative growth and reduce flowering.
During the immature stage, a combination inorganic and organic 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.
- 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;
- 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;
- Second year: fertilize with about 250 g (1/2 pound) every 3 months;
- Third year: Fertilize with about 450 g (1 pound) every 3 months;
- Mature trees: Mature longan trees require 1.5 to 2.25 kg (3.3 – pound) of fertilizer just before the tree blooms in late spring and again before of during the harvest;
- 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;
- If the soil 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;
- 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;
- Sprays 4-6 liquid feeds containing magnesium, manganese, zinc, molybdenum, and boron during the warm part of the year
Pruning of Mature Longan 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.
Pests, Insects, and Diseases
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 sp.) are other common pests that attack the tree.
Bats or flying foxes can eat up longan fruits during fruiting seasons. A protective net around the perimeter of the tree can be erected.
When Longan Tree Will Bear Fruit
Generally, the longan tree doen’t 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
- The longan trees don’t bear fruit every year;
- The fruits can be protected from birds by netting or bagging the fruit in paper bags;
- The longan fruit don’t continue to ripen after they are removed from tree unlike;
- Wait for the fruits to change their colour to light brown and size 2 cm or greater with good flavour;
- You may pick on fruit and taste for its sweetness before you harvest them;
- Caution: During the harvest, too much removal of leaves and wood with the fruit panicles can reduce flowering the next season;
- You can refrigerate the fruits in plastic bags for late use.
- Longan, Morton, J., 259-262. In: Fruits of Warm Climates. Julia F. Morton, Miami, FL. (1987).
- 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.
- 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).