Botanical name: Syzygium cumini
jambul, Java plum, jamun, jambolan,
Black plum, Jamun, Kalojam or Jam.
Syzygium cumini is fast-growing tree ranges up to 30m in India and Oceania; 12-15m in Florida. The bark on the lower part of the tree is rough, cracked, flaking and discolored. The fruit is round or oblong, often curved, usually turns from green to light-magenta, then dark-purple or nearly black as it ripens. The fruit is usually astringent, sometimes unpalatably so, and the flavor varies from acid to fairly sweet.
Syzygium cumini trees start flowering from March to April.
The flowers are fragrant and small, about 5 mm in diameter. S. cumini fruits develop by May or June and resemble large berries.
Ecology/environment to grow/habitat:
The Syzygium cumini tree can be grown on a wide range of soils. However, for high yield potential and good plant growth, deep loam and a well-drained soil is needed. Such soils also retain sufficient soil moisture which is beneficial for optimum growth and good fruiting. It can grow well under salinity and waterlogged conditions too. However, it is not recommended to grow Syzygium cumini on very heavy or light sandy soils. Soil pH preference: 5.6 to 6.0 (acidic).
It is a tropical species which prefer mean annual temperatures around 25-27°C though will grow in sub-tropical areas, being sensitive to frost when young but mature trees have been undamaged by short frosts in southern Florida.
S. cumini grows best in wet regions with annual rainfall generally in excess of 1000 mm and up to 4000 mm, and even in some of the wettest places in the world (10,000 mm), though it will tolerate drier sites especially when established and on stony and/or gravely soils.
The S. cumini tree grows well from sea-level to 6,000 ft. (1,800 m) but, above 2,000 ft. (600 m) it does not fruit but can be grown for its timber.
The tree occurs in the tropical and sub-tropical climates under a wide range of environmental conditions. Syzygium cumini is native to Bangladesh, India, Nepal, Pakistan, Sri Lanka, Malaysia, the Philippines, and Indonesia.
Economic Importance / Uses:
Wood uses: Sources of strong heavy timber which is commonly used for beams and rafters, posts, bridges, boats, oars, masts, troughs, well-lining, agricultural implements, carts, solid cart wheels, railway sleepers and the bottoms of railroad cars. It is a fairly satisfactory fuel.
Fruit uses: Jam fruit possesses considerable nutritive value. Apart from minerals, sugars, and proteins, it is a good source of iron also. Good quality jam juice is excellent for sherbet, Vinegar, syrup and "squash".
Medicinal Uses: The fruit is stated to be astringent, stomachic, carminative, antiscorbutic and diuretic. Cooked to a thick jam, it is eaten to allay acute diarrhea. The juice of the ripe fruit, or a decoction of the fruit, or jam vinegar, may be administered in India in cases of enlargement of the spleen, chronic diarrhea and urine retention.
Bark uses: Jam bark yields durable brown dyes of various shades depending on the mordant and the strength of the extract. The bark contains 8 to 19% tannin and is much used in tanning leather and preserving fishing nets.
Leaves uses: The leaves have served as fodder for livestock and as food for tassar silkworms.
Nectar uses: The jam tree is of real value in apiculture. The flowers have abundant nectar and are visited by bees.
Seed uses: Seed powder of Syzygium cumini has significantly
reduced bith blood sugars (4-5) and fasting.
Other uses: The tree is grown as shade for coffee in India and being wind-resistant is sometimes planted in dense rows as a windbreak, and if topped regularly, such plantings form a dense, massive hedge.