Java plum (Syzygium cumini, (L.) Skeels 1912)

Identity

Java plum (Syzygium cumini (L.) Skeels, 1912), also called Jambolan, Jambul, Black plum or Malabar plum, is an evergreen fruit tree in the Myrtaceae family and the genus Syzygium. Linnaeus first described it as Myrtus cumini in 1753; Skeels transferred it to Syzygium in 1912, 159 years later. ^{1 6}

Its fruit, Jamun, gives the species its common name in many South Asian languages. The French name jamelonier comes from Portuguese jambolão, itself borrowed from an Indian vernacular name for this dark, fleshy fruit. ⁴

Hindu tradition compares Krishna's dark complexion to the color of ripe Java plum fruit. The Indian subcontinent was long called jambudvîpa, “the island of jambu,” referring to the species' former abundance. ⁸

Recognition

Rapid growth produces a large tree, commonly 10 to 30 m (33 to 98 ft) tall depending on climate, with a trunk often dividing into several secondary trunks near the ground. Rough, dark gray bark at the base becomes smoother and lighter gray higher up. ^{2 3}

Opposite, leathery, glossy leaves measure 5 to 25 cm (2 to 10 in) long according to shoot age. Young leaves are pinkish and smell of turpentine, then become glossy dark green. The fragrant flowers attract insect pollinators despite measuring only 4 to 6 mm (0.16 to 0.24 in). White when they open, they turn pale pink before falling, leaving the numerous stamens. ²

Ripening brings a striking color sequence: green fruit passes through pink and bright red before becoming purple-black when fully ripe. Its sweet, slightly acidic, astringent flesh stains the tongue of anyone eating it. ^{4 2}

Useful taxonomy

The genus name Syzygium comes from Greek syzygos, “joined in pairs.” It describes the opposite leaves found in most species of the genus, including related clove and rose-apple trees. ⁶

Important botanical synonyms for this species include:

• Eugenia jambolana Lam., an older botanical name
• Eugenia cumini (L.) Druce, a botanical synonym
• Syzygium jambolanum (Lam.) DC., a synonymous name
• Myrtus cumini L., the original name

The name Eugenia jambolana remains common in older medical and pharmacological literature, particularly from India, although the accepted botanical name is Syzygium cumini. Both names refer to the same plant, but overlooking their relationship can distort a literature search. ¹

Habitat and range

Java plum's native range covers the Indian subcontinent and Southeast Asia, reaching Indonesia and, according to POWO, northern Queensland in Australia. It grows naturally in humid lowland tropical forests, along riverbanks and in seasonally flooded areas, from sea level to about 1800 m (5900 ft). ^{1 2}

Introductions reached Hawaii as early as 1870 and Florida from 1911 through the USDA. The tree subsequently spread through most tropical and subtropical regions, including Brazil, East Africa, the Caribbean and Pacific islands. ²

In several introduced territories, rapid growth and seed dispersal by birds and other fruit-eating animals have made it invasive. In Hawaii, French Polynesia and New Caledonia in particular, dense stands slow the regeneration of native forest. ⁵

Life cycle and reproduction

Flowering occurs in the local spring, followed by fruiting from early to late summer according to region and climate. An isolated tree can bear fruit, but bee pollination, notably by Apis dorsata in the Western Ghats, improves fruit set and provides an important share of local honey. ²

Fruit ripens two to three months after flowering, allowing several successive harvests. Usually containing one seed, the fruit supplies seed that quickly loses viability. Sow it fresh for germination in two to four weeks. ^{2 3}

A grafted tree begins bearing in four to seven years, compared with eight to ten years for a seedling. This explains the commercial preference for grafting. Seeds dispersed by birds, bats and monkeys also produce abundant natural regeneration around parent trees, helping the species spread beyond orchards. ²

Uses and risks

Java plum is primarily grown for fruit. Ripe, purple-black jamun is eaten fresh or made into juice, jam, vinegar and, in some regions, wine. Very astringent unripe fruit is poorly suited to eating directly and benefits from soaking in salt water before preparation. ²

Seeds and bark are used in traditional Indian medicine for diabetes and digestive complaints. Compounds such as ellagic acid and various flavonoids have been documented, but effectiveness remains debated in the scientific literature. ⁷ The tannin-rich bark was also formerly applied to burns. This practice is now discouraged because tannin absorbed through a wound poses a documented risk. No toxicity is recorded for domestic animals. ²

Dense, water-resistant wood traditionally serves for railroad ties, well surrounds and rustic furniture, despite being difficult to work. ²

Varieties, look-alikes and related plants

Indian markets are dominated by two types: Ra Jaman, with large, sweet, purple-fleshed fruit, and Kaatha, with small, acidic fruit mainly used for processing. Named cultivars such as Pharenda and Dabka also circulate in tropical fruit collections and are described as regular producers. ²

Check whether a young tree is grafted before buying it. A grafted tree bears in four to seven years rather than the eight to ten years needed by a seedling, and produces fruit matching the named variety. ²

Several hundred species belong to Syzygium, and some have similar dark fruit. The accepted scientific name, Syzygium cumini, is more reliable than fruit color alone, supported by the fruit's characteristic curved shape and tongue-darkening effect when eaten.

Main sources

• Plants of the World Online / Kew, Syzygium cumini (L.) Skeels
• Morton, J., Fruits of Warm Climates, Jambolan, Purdue University NewCROP
• Plants For A Future, Syzygium cumini
• INPN, Syzygium cumini species profile (Java plum, jambolan)
• IUCN Global Invasive Species Database, Syzygium cumini
• Integrated Taxonomic Information System, Syzygium cumini (L.) Skeels
• Ayyanar & Subash-Babu, PMC, phytochemical constituents and traditional uses of Syzygium cumini
• Wikipedia (en), Syzygium cumini, cultural and religious significance in India