Longan - Dimocarpus longan Lour.
Longan flesh
Fig. 1 

Longan fruit whole and showing the flesh
Fig. 2 magnifying glass
Longan fruit whole and showing the flesh

Leaves 'Konala'
Fig. 3 magnifying glass
Leaves of the 'Konala' longan

Paper Wasp foraging among the Dimocarpus longan malesianus fruit flowers.
Fig. 6 magnifying glass
Paper Wasp foraging among the Dimocarpus longan var. malesianus fruit flowers

Inflorescense
Fig. 7 magnifying glass
Inflorescense

Flower close-up
Fig. 8 magnifying glass
Flower close-up

Dimocarpus longan var. malesianus. Macro shot of a tiny Longan fruit bud
Fig.13  magnifying glass
Dimocarpus longan var. malesianus. Macro shot of a tiny Longan fruit bud

Dimocarpus longan young fruit
Fig. 14 magnifying glass

Lá và trái nhãn Xuồng Dimocarpus longan thuộc họ Bồ Hòn Sapindaceae
Fig. 15 magnifying glass
Lá và trái nhãn Xuồng Dimocarpus longan thuộc họ Bồ Hòn Sapindaceae

Longan fruit
Fig. 16 magnifying glass

Trunk
Fig. 22 magnifying glass

A broad, squat Longan tree at Pine Island Nursery laden with fruit.
Fig. 23 magnifying glass
A broad, squat Longan tree at Pine Island Nursery laden with fruit

Longan bunch
Fig. 31 magnifying glass

Dimocarpus longan ssp malesianus fruit, from Muara Lawa, West Kutai, East Kalimantan, Indonesia
Fig. 32 magnifying glass
Dimocarpus longan ssp malesianus fruit, from Muara Lawa, West Kutai, East Kalimantan, Indonesia

Fruit for sale in the market
Fig. 33 magnifying glass
Fruit for sale in the market


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Scientific name
Dimocarpus longan Lour.
Common names
English: longan, lungan, dragon eye, Spanish: longán, longana, French: longanier, oeil de dragon; Malaysian and Indonesian: leng keng; Thai: lam yai 1
Synonyms
Euphoria longana, Euphoria longan, Nephelium longana, Nephelium longan
Relatives
Lychee, rambutan, pulasan, akee, Spanish lime, soapberry 1
Family
Sapindaceae
Origin
Mayanmar (Burma), southern China, southwest India, Sri Lanka, Indochinese peninsula 1
USDA hardiness zones
10a-11b
Uses
Fruit; specimen or shade tree in the landscape
Height
30-40 ft (9.144-12.192 m)
Spread
30-40 ft (9.144-12.192 m)
Crown
Tends to be round or oblong
Plant habit
Evergreen; symmetrical; dense foliage
Growth rate
Slow
Trunk/bark/branches
Bark is corky; erect to spreading
Pruning requirement
Required to improve tree structure and bearing surface area
Leaves
Pinnately compound alternate leaves;  dark green, shiny, leathery; up to 12 in.(30 cm) long;  wavy margins; blunt pointed tips; 6-9 pairs of leaflets per leaf 1
Flower
Terminal, erect, 4-18 in. (10–45 cm); widely branched; Feb./March through April and the beginning of May1
Fruit
Round to ovoid; 3/4-1 7/16 in. (22–36 mm); thin peel, leathery; whitish pulp; one seed
Season
Late August and September
USDA Nutrient Content - dry pdf
USDA Nutrient Content - raw pdf
Light requirement
Full sun
Soil tolerances
They do well on sandy loams, sand and calcareous, rocky soils of south Florida
PH preference
5.5-7.0
Drought tolerance
Tolerant
Flood tolerance
Not tolerant of excessively wet or flooded conditions
Soil/aerosol salt tolerance
Not tolerant of saline wind or soil condition
Wind tolerance
Wind resistant
Cold tolerance
Young trees may be killed at 26-28 °F (-2-3°C), mature trees tolerant, but branches are injured at 25-26°F (-3-4°C) with very severe damage or death below 24°F (-4°C) 1
Plant spacing
22-25 ft (6.7–7.6 m)
Invasive potential *
None reported
Pestdisease resistance
Scales, lychee webworm
Known hazard
None

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Reading Material

Longan Growing in the Florida Home Landscape from the University of Florida pdf 9 pages
Longan from Julia Morton's book Fruits of Warm Climates
The Longan from W. Popenoe's book Manual of Tropical and Subtropical Fruits



Often considered the poorer cousin of the illustrious lychee, the longan is very popular in its own right. Fruits vary in size, but are usually about the size of a very large grape. The thin yellow-brown skin encloses a translucent white pulp surrounding a single dark seed, hence the name "Dragon's Eye." 6

Origin

Native to Asia, longan was introduced here in the early 1900s and is grown in Hawaii, California, and South Florida. There are numerous cultivars of longan; 'Kohala' is the variety most planted in Florida. 4

Description
The longan is a large evergreen tree that is becoming very popular in South Florida landscapes. Native to southeast Asia, this beautiful tree produces showy clusters of grape-like fruit during the mid-to-late summer. Trees can grow as high as forty feet or more and are well-adapted for a wide variety of soil and moisture conditions. 3

Young treeLongan 'Kohala'Dimocarpus longan (Longan, dragon's eye)Habit at Wailuku, Maui, HawaiiBase of old tree
Fig. 24 magnifying glass Fig. 25 magnifying glass Fig. 26 magnifying glass Fig. 27 magnifying glass

Fig. 24. Young tree
Fig. 25. Longan 'Kohala'
Fig. 26. Dimocarpus longan (Longan, dragon's eye) Habit at Wailuku, Maui, Hawaii
Fig. 27. Base of an old tree

Leaves

LeavesDimocarpus longan (Longan, dragon's eye) Habit at Garden of Eden Keanae, Maui, Hawaii
Fig. 4 magnifying glass Fig. 5 magnifying glass

Fig. 5. Dimocarpus longan (Longan, dragon's eye)Habit at Garden of Eden Keanae, Maui, Hawaii

Flowers
The inflorescence is commonly called a panicle. Flowers on the panicle are held on numerous cymules on the many branchlets of the panicle. The flowers are small and have 5 to 6 sepals and petals, and are brownish yellow or greenish yellow, with a two-lobed pistil and usually 8 stamens. Panicles may carry a few to more than 350 fruit. There are 3 flower types in longan, staminate (functionally male), pistillate (functionally female) and hermaphroditic (bisexual). Flowering in each panicle occurs in progressive openings of staminate (male) flowers first, then hermaphroditic flowers functioning as females and then hermaphroditic flowers functioning as males. 1

InflorescenseDimocarpus longan Lour. Alor Setar, Kedah, MalaysiaDimocarpus longan (Longan, dragon's eye) Flowers
Fig. 9 magnifying glass Fig. 10 magnifying glass Fig. 11 magnifying glass
Fruit forming
Fig. 12 magnifying glass

Fruit
The drupaceous fruit are spherical to ovoid, ¾ to 1 7/16 inches (22–36 mm) in diameter and 0.21 to 0.67 oz (6–19 g) in weight (Figure 4). The peel is tan or light brown, thin, leathery and smoother than that of the lychee. The pulp is whitish and translucent; thin in large seeded fruits and medium thick to thick in others. Fruit have 1 seed; globular and shiny, brown to dark brown. The pulp does not adhere to the seed and is flavorful and sweet with 12-21% soluble solids. 1

Fruit developpingLongan "Kahola' fruitLongan fruit
Fig. 17 magnifying glass Fig. 18 magnifying glass Fig. 19 magnifying glass
Longan Fruit in Adelaide/AustraliaLongan fruit, skin, pulp and seed
Fig. 20 magnifying glass Fig. 21 magnifying glass

Fig. 18. Longan 'Kahola' fruit

Thinning
Longan fruit set varies greatly among trees and years. In some years, individual longan panicles set in excess of 300 fruit. However, panicles with 150 or more fruit usually produce small fruit. Removing about 50% of the set fruit during the spring usually results in a large increase in fruit size. Thinning is best done when fruit are ¼ to ½ inches (6-12 mm) in diameter and consists of removing one half to two-thirds of the distal (terminal) end of each panicle. 1

Dr. Crane thinning a paniclePlacement of the pruning cutResults of pruning
Fig. 28 magnifying glass Fig. 29 magnifying glass Fig. 30 magnifying glass

Fig. 28. Dr. Crane, University of Florida TREC, thinning a panicle
Fig. 29. Placement of the thinning cut
Fig. 30. Results of thinning

Varieties Page
Reliable bearing is the major production problem for longan throughout the world. In Florida, 99% of the acreage is planted with 'Kohala'. Other cultivars have been introduced, some for a long time and others recently. A number of new and re-introductions including 'Edau' ('Daw'), 'Chompoo', 'Haew', and 'Biew Kiew' are under evaluation by several institutions and producers. However, nothing superior to 'Kohala' has been identified. 1
One of the recently introduced cultivars is named 'Diamond River'. This cultivar is from Thailand and is reported to fruit every year, be precocious, produce off-season, and produce a sizeable late season crop. However, fruit quality is only fair and the tree is very susceptible to limb breakage. 1

Harvesting
The longan harvest season in south Florida is from the middle of July to early September but is mainly in August. At maturity, the fruit will be an intense tan color. The main ripeness indicator is pulp sweetness; this occurs before removing the fruit from the tree. Fruit that is 1¼ inches (32 mm) or greater in diameter with good flavor is most desirable. Once removed from the tree, the fruit will not increase in sweetness. 1
Time flowering to harvest: 140-190 days. 1

Propagation
Trees can be seed-propagated, but seedlings do not come true to type and may take up to six to eight years to start bearing. A more practical way of propagation is by air layering, which takes about eight to ten weeks, or veneer grafting on seedling rootstocks. Air-layered trees generally will bear within one to two years after being planted and grafted trees may bear the next year after being planted. 3 April through August is the best time to perform this task, and roots begin to form within 10 - 12 weeks. No special or improved rootstocks have been reported. 8

Pruning
At planting or soon afterward, remove limbs with a narrow crotch angle. To force new shoot growth and increase the number of new shoots either bend long upright limbs to a horizontal position by tying or head back upright limbs. Shoot tip removal (removing 1-2 inches of the end of new shoots), once or twice during spring and summer will increase branching and make the tree more compact. As trees mature, most of the pruning is done to control tree size (height and width), and to maintain production of the lower tree canopy and light on all sides of the canopy. If the canopy of the tree becomes too dense, selective removal of some branches will increase air circulation and light penetration. 1
Trees kept 10 to 15 ft high (3.1–4.6 m) and 15 to 30 ft (4.6–9.1 m) wide are easier to care for and pick. They are also less likely to topple during strong winds. If the canopy of the tree becomes too dense, selective removal of some branches will increase air circulation and light penetration. 1

Fertilizing
See Longan Growing in the Florida Home Landscape from the University of Florida pdf 9 pages

Irrigation
Withholding or reducing watering during the late summer/early fall through winter is recommended to stop or reduce excessive vegetative growth and enhance subsequent flowering during the spring. However, for optimum fruit production and quality, regular irrigation is recommended from flowering through harvest. 1

Pest Page
Longans have a few insect problems in south Florida. The most common pests are the lychee webworm and several scale insects. 1

Disease Page
There are no major disease problems of longan at the present time. Red alga (Cephaleuros virescens) attacks limbs and shoots and is most prevalent during high humidity, warm, rainy weather. Parasitic lichen (Strigula sp.) may parasitize leaves. Please contact your local UF/IFAS Extension office for current control recommendations. 1

Food Uses

Longans produced in south Florida are consumed fresh or are frozen for later consumption. 1
In China, the majority are canned in syrup or dried. For drying (Fig. 34), the fruits are first heated to shrink the flesh and facilitate peeling of the rind. Then the seeds are removed and the flesh dried over a slow fire. The dried product is black, leathery and smoky in flavour and is mainly used to prepare an infusion drunk for refreshment. 2

Dried fruit
Fig. 34 magnifying glass

Medicinal Uses **
The flesh of the fruit is administered as a stomachic, febrifuge and vermifuge, and is regarded as an antidote for poison. A decoction of the dried flesh is taken as a tonic and treatment for insomnia and neurasthenic neurosis. In both North and South Vietnam, the "eye" of the longan seed is pressed against a snakebite in the belief that it will absorb the venom. 2

Other Uses
A liqueur is made by macerating the longan flesh in alcohol. 2
The seeds, because of their saponin content, are used like soapberries (Sapindus saponaria L.) for shampooing the hair. The seeds and the rind are burned for fuel and are part of the payment of the Chinese women who attend to the drying operation. 2

General
Fusing the Ancient With the Modern
"Longan trees growing near temples in that country," says Matsumoto, "were found to form flowers and then bear fruit shortly after religious ceremonies in which fireworks were used. This occurred even outside the typical growing season."
Studies reported in 2000 by Chung-Ruey Yen of the National Pingtung University of Science and Technology in Taiwan suggested that a chemical in the ashes of the firecrackers settled in soil around the trees and triggered flowering. 7


Further Reading
Florida Growers Like Lychees and Longans from the USDA Agriculture Research Service
Longan Production in Asia from the Food and Agriculture Orgainzation of the United Nations pdf 21 pages
Longan Videos with Dr. Jonathan Crane, University of Florida TREC ext. link
Longan from the Archives of the Rare Fruit Council of Australia, 1980
Longan by Gene Joyner from the Archives of the Rare Fruit Council of Australia, 1995
Florida Food  Fare: Longans from the University of Florida pdf
New Options for Lychees and Longans Fans and Farmers from the USDA Agriculture Research Service
Longan Botanical Art


List of Growers and Vendors


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Bibliography

1 Crane, Jonathan H. ,Balerdi, Carlos F. Sargent, Steven A. and Maguire, Ian. "Longan Growing in the Florida Landscape." edis.ifas.ufl.edu.. Fact Sheet HS-49, a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication Nov. 1978. Revised Apr. 1994, Nov. 2000, Sept. 2005, Oct. 2008, and Nov. 2016. Web. 8 Jan. 2017.

2 Morton, J. "Longan." hort.purdue.edu. Fruits of warm climates, p. 259-262. 1987. Web. 13 Mar. 2015.

3 Joyner, Gene. "Longan." rfcarchives.org.au. Archives of the Rare Fruit Council of Australia. Tropical Fruit News Vol. 28 No. 10. May 1995. Web. 17 Mar. 2015.

4 "Longan." gardeningsolutions.ifas.ufl.edu. Web. 21 Mar. 2015.

5 "Dimocarpus longan." tropical.theferns.info. worldagroforestry.org. Web. 21 Mar. 2015.

6 "Longan, Dimocarpus longana a.k.a. Euphoria longana, "Dragon's Eye"." tradewindsfruit.com. Web. 21 Mar. 2015.

7 Wood, Marcia. "New Options for Lychee and Longan Fans and Farmers." ars.usda.gov. USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. May 2004. Web. 22 Mar. 2015.

8 Mossler, Mark. "Florida Crop/Pest Management Profile: Lychee and Longan." edis.ifas.ufl.edu. This document is CIR1400, one of a series of the Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Publication date Mar. 2002. Revised in June of 2009. Reviewed June 2012. Web. 23 Mar. 2015

Photographs

Fig. 1,24 Longan, Dragon's Eye. N.d. Tropical Plant Catalog. toptropicals.com. Web. 23 Jan. 2014.
Fig. 2,20
Surukuku (Nelson Ramos-Lopes). Fruta LONGAN (Dimocarpus longan Lour.). 2007. commons.wikimedia.org. Public Domain. Web. 20 Mar. 2015.
Fig. 3,7,16,18,19,25,28.29,30 Maguire, Ian. 'Kohala' longan. N.d. University of Florida. edis.ifas.ufl.edu Web. 23 Jan. 2014.
Fig. 4,13
Sinyem, Richard Wellis. Paper Wasp foraging among the Dimocarpus longan malesianus fruit flowers. 2010.  flickr.com.  rwsphoto.blogspot.com. Under (CC BY-NC 2.0).  Web. 8 Jan. 2017.
Fig. 5 Starr, Forest & Kim. Dimocarpus longan (Longan, dragon's eye) Habit at Garden of Eden Keanae, Maui, Hawaii. 2011. starrenvironmental,.com. Under (CC BY-NC 2.0). Web. 10 Jan. 2017.

Fig. 4,8,9,12,17,22 Kwan. Dimocarpus longan ssp. longan. 2011. natureloveyou.sg. Web. 17 Mar. 2015.

Fig. 10 Morad, Ahmad Fuad. Dimocarpus longan Lour. Alor Setar, Kedah, Malaysia. 2011. flickr.com. Under (CC BY-NC-SA 2.0). Web. 8 Jan. 2017.
Fig. 11 Starr, Forest & Kim. Dimocarpus longan (Longan, dragon's eye) flowers. 2009. Enchanting Floral Gardens of Kula, Maui, Hawaii. starrenvironmental,.com. Under (CC BY-NC 2.0). Web. 10 Jan. 2017.
Fig. 14 Cerlin Ng. Dimocarpus longan. 2013. flickr.com. Under (CC BY-NC-SA 2.0). Web. 8 Jan. 2017.
Sinyem, Richard Wellis. Dimocarpus longan var. malesianus. Macro shot of a tiny Longan fruit bud. 2010. flickr.com.  rwsphoto.blogspot.com. Under (CC BY-NC 2.0).  Web. 8 Jan. 2017.

Fig. 15 Duy Thuong Ngo 吳 惟 尚. Lá và trái nhãn Xuồng Dimocarpus longan thuộc họ Bồ Hòn Sapindaceae. 2011. flickr.com. Under (CC BY-NC 2.0). Web. 10 Jan. 2017.

Fig. 21 Dezidor. Fruits. N.d. tropical.theferns.info. Web. 21 Mar. 2015.

Fig. 23 Pouletic. A broad, squat Longan tree at Pine Island Nursery laden with fruit. 2011. commons.wikimedia.org. Under (CC BY-SA 3.0). Web. 20 Mar. 2015.

Fig. 24 Nguy?n Thanh Quang. Dried fruits. N.d. tropical.theferns.info. Under (CC BY-SA 3.0). Web. 21 Mar. 2015.

Fig. 26 Starr, Forest & Kim. Dimocarpus longan (Longan, dragon's eye) Habit at Wailuku, Maui, Hawaii. 2009. starrenvironmental,.com. Under (CC BY-NC 2.0). Web. 10 Jan. 2017.
Fig. 27 Jimmie.  Base of an old tree. N.d. tropical.theferns.info. Under (CC BY-NC 2.0). Web. 10 Jan. 2017.
Fig. 31 Van der Giessen, Elijah. Dimocarpus longan, from Edmonton, Canada. 2004. flickr.com. Under (CC BY-NC 2.0). Web. 21 Mar. 2015.

Fig. 32 Wie146. Dimocarpus longan ssp malesianus fruit from Muara Lawa, West Kutai, East Kalimantan, Indonesia. 2007. commons.wikimedia.org. Under (CC BY-SA 3.0). Web. 20 Mar. 2015.

Fig. 34 Patrice 78500. Fruits for sale in the market. N.d. tropical.theferns.info. Web. 21 Mar. 2015.

UF/IFAS Assessment of Non-native Plants in Florida's Natural Areas
** Information provided is not intended to be used as a guide for treatment of medical conditions.

Published 12 Apr. 2014 LR. Last Update 11 Jan. 2017 LR
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