Java plum, Okeechobee News

Article from Okeechobee News
by Dan Culbert - Okeechobee County Extension Horticulture Agent, Retired

Java Plum

An office visitor once sent me a photo a large tree that had taken over her new Okeechobee homestead. While cleaning “Florida holly” trees (a.k.a. Brazilian Peppertrees), they found a bunch of other rapidly growing trees with a fruit that tastes similar to a grape, with a dark purple covering and white meat inside. The trees were loaded with this fruit. They wanted to know what it was, and if the fruit was safe to eat.

Fig. 1

Cluster of Java Plum Trees

Having seen this plant in my West Palm Beach yard several years ago, I recognized it as an exotic tree known as the Java Plum. Among its many names are Jambolan, Jambu and many other names that include ‘plum’. (Botanically it is known as Syzygium cumini).

The java plum is fast-growing, reaching full size in 40 years. It ranges up to 40 or 50 ft tall in Florida; and it may attain a spread of 36 ft with a trunk diameter of 2 or 3 ft. It usually forks into multiple trunks a short distance from the ground. The bark on the lower part of the tree is rough, cracked, flaking and discolored; further up it is smooth and light-gray.

The turpentine-scented evergreen leaves are opposite, 2 to 10 in. long, 1 to 4 in. wide; oblong-oval or elliptic, blunt or tapering to a point at the apex; pinkish when young; when mature, leathery, glossy, dark-green above, lighter beneath, with conspicuous, yellowish midrib.

Fig. 2

Foliage and fruit

Flowers

Fig. 3

Flowers

The fragrant flowers, in 1-to 4-in clusters, are 1/2 in wide, 1 in (2.5 cm) or more in length; have a funnel-shaped calyx and 4 to 5 united petals, white at first, then rose-pink, quickly shed leaving only the numerous stamens. These are typical flower forms for the Myrtle family.

The fruit, in clusters of just a few or 10 to 40, is round or oblong, often curved; 1/2 to 2 in. (1.25-5 m) long, and usually turns from green to light-magenta, then dark-purple or nearly black as it ripens. (A white-fruited form has been reported in Indonesia.) The skin is thin, smooth, glossy, and adherent. The pulp is purple or white, very juicy, and normally encloses a single, oblong, green or brown seed, up to 1½ in. in length. The fruit is usually astringent, sometimes unpalatably so, and the flavor varies from acid to fairly sweet. The main fruiting season in India and southern Florida (where the tree blooms principally in February and March) extends through late May, June and July. Small second crops from late blooms have been observed in October. Individual trees may habitually bear later than others.

Fruit

s
Fig. 4

Fruit, showing interior and cluster

Jambolan fruit of good size and quality, having a sweet or subacid flavor and a minimum of astringency, are eaten raw and may be made into tarts, sauces and jam. I have also been contacted by persons in the US that are native to southern Asia that appreciate this fruit from their native countries. They have said they are willing to have it shipped to them; however, this violates weed laws and it is doubtful the fruit would hold up to the rigors of modern package delivery services.

The jambolan is native in India, Burma, Ceylon and the Andaman Islands. It was long ago introduced into and became naturalized in Malaya. In southern Asia, the tree is venerated by Buddhists, and it is commonly planted near Hindu temples. Java Plum fruit has been made into wine, vinegar. In some areas it is a valuable “nectar tree” for honeybees. Because of its fast growth rates, considerable wood can be produced in a few years. Jambolan lumber is used for industrial purposes such as crates and posts; in rural areas it has been used as a windbreak, and resistant to coastal high winds, but not to heavy salt spray.

In 1911 the USDA Bureau of Plant Industry received jambolan seeds from the Far East. The tree flourished in Santa Barbara California, although fruit production is poor in that climate. In southern Florida, the tree was rather commonly planted in the past. Heavy fruit crops may litter streets, sidewalks and lawns, attracting insects, rapidly fermenting and creating a foul atmosphere. Most Floridians are eager to have the trees cut down. Where conditions favor spontaneous growth, the seedlings become a nuisance, as well.

Seed lose their viability rapidly, and vegetative propagation by cuttings and grafting has been used with this plant. In the wild, seeds contained in the fruit are spread by birds and mammals, including raccoons and wild hogs. (In Hawaii, mynah birds are the primary transportation means for the java plum.)

The jambolan has received far more recognition in folk medicine and in the pharmaceutical trade than in any other field. Preparations of fruit, leaves, bark and seed have been suggested to be effective for various ailments – but reliable medical research on these uses is not well reported in the scientific literature.

My office caller reported that these java plums have created a small forest of their own, growing on the bank of the canal and crossing over to another piece of property. Once recommended as a shade tree, it has been considered naturalized in southern Florida since 1982, forming dense canopies that shade out young native trees in wet pinelands, hammocks, and well drained uplands.

Back to
Jambolan Page

Bibliography

Culbert, Daniel F. “Java Plum.” Feature Article for Okeechobee News, August 4, 2004, 2018, UF/IFAS, Okeechobee County Extension Service, okeechobee.ifas.ufl.edu.
Morton, J. "Jambolan." Fruits of warm climates, Winterville, N.C Creative Resource Systems, 1987, newcrop.hort.purdue.edu/newcrop/morton/jambolan.html.
Langeland, K., and Berks. "Identification of Invasive Plants." Gainesville: UF/IFAS Extension Service. plants.ifas.ufl.edu/syzcum.pdf.

Photographs

Fig. ¹ Culbert, D. F. "Cluster of Java Plum Trees growing in Okeechobee FL." UF/IFAS, Okeechobee County Extension Service, okeechobee.ifas.ufl.edu.
Fig. ² Culbert, D. F. " Leaves and fruit of Jambolan." UF/IFAS, Okeechobee County Extension Service, okeechobee.ifas.ufl.edu.
Fig. ³ Murray, Anne. "Flowers." UF/IFAS Center for Aquatic and Invasive Plants assessment, assessment.ifas.ufl.edu/assessments/syzygium-cumini/.
Fig. ⁴ "Fruit, showing interior and cluster." Australian Rare Fruit Review, plant.daleysfruit.com.au/l/jambolan-plum-syzygium-cumini-14173.jpeg. Accessed 1 June 2018.

Published 3 June 2018 LR