The Dragon’s Eye (Dimocarpus longan), commonly known as longan, is a tropical fruit tree belonging to the Sapindaceae family, the same family as Lychee and Rambutan. It is widely cultivated for its sweet and aromatic fruits, consumed fresh or processed in various ways in Asian cuisine. In addition to its significant economic value in Asian countries, the species also has ecological and medicinal importance, integrating its cultivation and traditional medical practices.
Native to southern China and other regions of Southeast Asia, including Thailand, Vietnam, and Indonesia, the Dragon’s Eye thrives in tropical and subtropical climates, preferring well-drained and slightly acidic soils. In its natural habitat, it grows in humid tropical forests, where temperature and humidity conditions are ideal for its development.
The species has been cultivated for over two thousand years, and some records indicate that during the Han dynasty, around 200 BC, the emperor ordered the planting of longan trees in the gardens of his palace in Shaanxi, although the saplings did not thrive. Centuries later, the cultivation of the Dragon’s Eye flourished in other areas of China, such as Fujian and Guangdong, becoming an important economic activity. The introduction of longan in countries like Australia, Thailand, Hawaii, and Florida occurred between the 19th and 20th centuries, driven by migration and the demand for traditional foods.
The name of the genus Dimocarpus comes from the Greek “dimos,” meaning “double,” and “karpos,” meaning “fruit,” referring to the fruit’s morphology. The specific epithet longan is an adaptation of the plant’s common name in Cantonese, “lùhng ngáahn” (龍眼), which translates to “dragon’s eye”, referring to the appearance of the fruit, whose translucent flesh and central dark seed resemble an eyeball.
Dragon’s Eye is a perennial tree of medium to large size, reaching heights of up to 98 feet (30 meters) under ideal conditions. Its roots are deep, and the trunk is robust, with a diameter that can exceed 31 inches (80 centimeters), and presents thick, fissured, and barky bark. The branches are long, thick, and generally drooping, giving the canopy a rounded shape.
The leaves are compound, alternate, and pinnate, usually with 6 to 9 pairs of leaflets per leaf. The leaflets are oblong, with a rounded apex, measuring approximately 4 to 6 inches (10 to 15 centimeters) in length and 0.8 to 2 inches (2 to 5 centimeters) in width. The upper surface is dark green and glossy, while the lower side is lighter. The leaves have pinnate veins and are leathery, providing resistance to water loss.
The inflorescence of Dimocarpus longan is terminal, panicle-type, with broad branches and numerous small flowers. The flowers are unisexual, featuring male, female, and hermaphrodite flowers in the same inflorescence, characterizing the species as polygamo-monoecious. Flowering usually occurs in late spring and early summer, depending on local climate conditions.
The flowers are small, with about 5 to 6 sepals and petals ranging from pale yellow to light brown in color. Male flowers have eight stamens and a rudimentary pistillode, while female flowers feature a bicarpellate ovary and staminodes. The hermaphrodite flowers contain both stamens and a functional ovary. Pollination is primarily carried out by insects, attracted by the nectar and the scent of the flowers.
The fruits are spherical drupes, about 0.8 to 1.2 inches (2 to 3 centimeters) in diameter, clustered in hanging bunches. The skin is thin, leathery, and light brown to yellowish when ripe, with a slightly rough texture. The pulp is translucent, juicy, and sweet, encasing a single central seed. The seed is spherical, hard, and shiny black with a white spot at the base, giving the fruit the appearance of a “dragon’s eye.”
Fruition usually occurs in the summer, following flowering. The fruit matures progressively, and harvesting is done when the fruits reach the typical size and color. Generally, Longan fruits mature later than Lychee.
In Chinese culture, Longan is considered an auspicious fruit, associated with prosperity and family. Furthermore, it is used in traditional Chinese medicine to relieve stress, improve sleep quality, and strengthen the immune system. It is said that its aroma is more delicate and less acidic than Lychee’s, and its flavor reminiscent of musk, dates, and ripe avocado.
Dragon’s eye has a variety of uses beyond fresh consumption. In Asian cuisine, it is commonly found in soups, desserts, and sweet-and-sour dishes, and can be consumed fresh, dried, or canned in syrup. The dried fruit is often used in sweet soups and infusions, attributed in traditional medicine with relaxing effects. Moreover, Longan is used in wine production in some regions of Southeast Asia.
In landscaping, Dimocarpus longan is valued for its dense canopy, drooping branches, and dark green evergreen leaves, providing ample shade in gardens and parks. Its flowering, composed of small flowers grouped in panicles, attracts pollinators like bees, contributing to local biodiversity. The fruit, besides being tasty, adds aesthetic value to the tree during the fruiting period.
Due to its medium to large size, it is suitable for large spaces, where it can be used as a standalone tree or in tree compositions aimed at creating shaded and pleasant areas. Planting the dragon-eye in the home orchard is an excellent choice due to its dual ornamental and productive function, offering tasty and exotic fruits, as well as contributing beauty and shade to the environment.
Additionally, Longan can be grown in pots, especially during the early years of growth or when limiting its size is desired. However, for successful container cultivation, it is essential to choose a large pot, a full-sun location, and a seedling preferably propagated by vegetative methods and already fruiting, as well as to perform regular pruning to control the plant’s size. Although fruiting in pots is possible, it tends to be less abundant than in specimens planted directly in the garden.
The dragon-eye thrives in locations with high sunlight incidence, preferring full sun, with more than 6 hours of direct light per day. It adapts better to tropical and subtropical regions, where temperatures are high and relative humidity is elevated. While it tolerates light frosts, temperatures below 32°F (0°C) can cause significant damage to the plant.
The ideal soil for cultivating dragon-eye should be fertile, well-drained, and slightly acidic. Heavy clay soils or those with inadequate drainage are not recommended as they can lead to root rot. For growing in pots, it is recommended to use a potting mix composed of a balanced blend of garden soil, coarse sand, and organic matter, ensuring good aeration and drainage.
The planting of Dimocarpus longan should ideally be carried out at the beginning of the rainy season, taking advantage of natural moisture to enhance root establishment. Planting beds should be adequately sized to accommodate the root system, typically 24x24x24 inches (60x60x60 cm), and should be prepared in advance, incorporating organic matter to enhance soil fertility.
Irrigation should be regular, especially in the first years after planting, keeping the soil moist but not waterlogged. During the fruiting phase, the demand for water increases, making it crucial to monitor soil moisture to ensure the production of high-quality fruits. Lack of water during this phase seriously compromises the plant’s yield.
Fertilization should be balanced, with periodic applications of fertilizers rich in nitrogen, phosphorus, and potassium, as well as essential micronutrients. Fertilizers suitable for fruit trees are recommended. Staking is advisable for young saplings, providing support against strong winds and aiding in the plant’s vertical development.
Pruning should be carried out to remove dry, diseased, or poorly formed branches, as well as to promote aeration and light penetration inside the crown, which contributes to the overall health of the tree and improves fruit production. Maintenance includes constant monitoring of pests and diseases, controlling weeds around the tree, and periodically renewing the layer of organic matter in the soil. Applying acolchado (mulching) in the area under the tree canopy favors soil moisture and the productivity of Longan.
Longan exhibits moderate resistance to various adverse conditions. It tolerates moderate winds, but in regions prone to intense storms, the use of windbreaks or appropriate staking is advisable to protect the plant. Moreover, Longan can be cultivated in coastal areas, provided it is protected from strong saline winds, which can impair its development. Among the most common pests that can affect Longan are sucking insects, such as aphids, mites, and scale insects, which feed on the plant’s sap and can transmit diseases. Additionally, defoliating caterpillars can cause significant damage to the leaves.
Anthracnose, caused by fungi of the genus Colletotrichum, is a concern, affecting leaves, flowers, and fruits, especially in conditions of high humidity. Controlling these adversities involves practices such as pruning affected parts, using appropriate insecticides and fungicides, and preventive measures like correct spacing between plants to enhance air circulation, preventive applications of Bordeaux mixture, and reducing humidity.
Longan propagation can be done by seeds or by vegetative methods, such as air layering and grafting. Cultivation from seeds is more common in home gardens but is less recommended for commercial purposes, as plants originated from this method may take between 8 and 10 years to begin fruiting and show greater genetic variability. Planting
Longan by seeds should be done with freshly harvested, depulped seeds sown immediately at a maximum depth of 0.8 inches (2 cm), thus preventing the emergence of multiple stems. Germination occurs between 7 and 10 days under adequate conditions of moisture and warmth. Seedlings should grow in a shaded location during the first year and, in the following spring, are transplanted into rows in a nursery. The final planting in the field occurs after 2 to 3 years, preferably during the dormancy period in winter, ensuring better adaptation and development.
Plantlets propagated by air layering are preferred in large plantations, as they maintain the characteristics of the parent plant and enter production more quickly. Longan plantlets obtained through air layering can begin to bear fruit in approximately 2 years after planting. Longan is a long-lived tree, and its maximum production occurs between 10 and 20 years of age.
