The term "rose apple" (in French, pomme rose, pommier rose; in Spanish, poma rosa, pomarrosa, manzana rosa, or manzanita de rosa) is so widely employed that the species has few alternate names apart from those in the many local dialects of Africa, India, Malaya, southeastern Asia, the East Indies and Oceania. It is sometimes called jambosier by French-speaking people, plum rose or malabar plum in the English-speaking West Indies, pommeroos or appelroos in Surinam, and jambeiro or jambo amarelo in Brazil; jaman in India, and yambo in the Philippines.
|Fig. 103: The rose apple (Syzygium jambos) is a minor fruit, but the tree is a quick-growing source of fuel and other products.|
The rose apple tree may be merely a shrub but is generally a tree reaching 25 or even 40 ft (7.5-12 m) in height, and has a dense crown of slender, wide-spreading branches, often the overall width exceeding the height. The evergreen leaves are opposite, lanceolate or narrow-elliptic, tapering to a point; 4 to 9 in (10-22 cm) long, and from 1 to 2 1/2 in (2.5-6.25 cm) wide; somewhat leathery, glossy, dark-green when mature, rosy when young. The flowers are creamy-white or greenish-white, 2 to 4 in (5-10 cm) wide, consisting mostly of about 300 conspicuous stamens to 1 1/2 in (4 cm) long, a 4-lobed calyx, and 4 greenish-white, concave petals. There are usually 4 or 5 flowers together in terminal clusters. Capped with the prominent, green, tough calyx, the fruit is nearly round, oval, or slightly pear-shaped, 1 1/2 to 2 in (4-5 cm) long, with smooth, thin, pale-yellow or whitish skin, sometimes pink-blushed, covering a crisp, mealy, dry to juicy layer of yellowish flesh, sweet and resembling the scent of a rose in flavor. In the hollow center, there are 1 to 4 brown, rough-coated, medium-hard, more or less rounded seeds, 3/8 to 5/8 in (1-1.6 cm) thick, which loosen from the inner wall and rattle when the fruit is shaken. Fragments of the seedcoat may be found in the cavity.
Origin and Distribution
The rose apple is native to the East Indies and Malaya and is cultivated and naturalized in many parts of India, Ceylon and former Indochina and the Pacific Islands. It was introduced into Jamaica in 1762 and became well distributed in Bermuda, the Bahamas, the West Indies and, at low and medium elevations, from southern Mexico to Peru. In Guatemala, the tree may be planted as a living fencepost or in hedgerows around coffee plantations. For this purpose, it is drastically pruned to promote dense growth. It grows wild abundantly, forming solid stands and thickets, in Puerto Rico, the Virgin Islands, Guatemala, Honduras and Panama.
In 1825, eight young trees were taken from Rio de Janeiro to Hawaii by ship, and, in 1853, a United States warship delivered avocado and rose apple trees from Central America to the island of Hilo. The rose apple became naturalized on the islands of Kauai, Molokai, Oahu, Maui and Hawaii. In 1893, it was reported as already cultivated in Ghana. It is semi-naturalized in some areas of West Tropical Africa and on the islands of Zanzibar, Pemba and Reunion. It is believed to have been first planted in Queensland, Australia, about 1896. A tree obtained from an Italian nursery has grown and borne well on the coastal plain of Israel. However, it is not of interest there as a fruit tree but rather as an ornamental.
The rose apple was introduced into Florida, at Jacksonville, before 1877, but, as a fruit tree, it is suited only to the central and southern parts of the state. In California, it is planted as far north as San Francisco for its ornamental foliage and flowers. Because the tree occupies considerable space and the fruit is little valued, the rose apple has not been planted in Florida in recent years, though there are quite a number of specimens remaining from former times.
The rose apple flourishes in the tropical and near-tropical climates only. In Jamaica, it is naturalized from near sea-level up to an altitude of 3,000 ft (915 m); in Hawaii, from sea-level to 4,000 ft (1,200 m). In India, it ranges up to 4,400 ft (1,350 m); in Ecuador, to 7,500 ft (2,300 m). At the upper limits, as in California, the tree grows vigorously but will not bear fruit.
In India, it does best on the banks of canals and streams and yet tolerates semi-arid conditions. Prolonged dry spells, however, are detrimental.
A deep, loamy soil is considered ideal for the rose apple but it is not too exacting, for it flourishes also on sand and limestone with very little organic matter.
Most rose apple trees are grown from seeds, which are polyembryonic (producing 1 to 3 sprouts), but the seedlings are not uniform in character nor behavior. In India, vegetative propagation has been undertaken with a view to standardizing the crop and also to select and perpetuate dwarf types. Using cuttings, it was found that hardwood does not root even with chemical growth promoters. Treated semihard wood gave 20% success. Air-layers taken in the spring and treated with 1,000 ppm NAA gave 60% success. Air-layers did not root in the rainy season. In budding experiments, neither chip nor "T" buds would take. Veneer grafting in July of spring-flush scions on 1-year-old rootstocks was satisfactory in 31% of the plants. In West Bengal, air-layering is commonly performed in July and the layers are planted in October and November. Fruiting can be expected within 4 years. Sometimes the rose apple is inarched onto its own seedlings.
Rarely do rose apple trees receive any cultural attention. Some experimental work has shown that seedless, thick-fleshed fruits can be produced by treating opened flowers with growth regulatorsnaphthoxy acetic acid (NOA), 2,4,5-T, or naphthalene acetic acid.
In Jamaica and Puerto Rico, the rose apple trees bloom and fruit sporadically nearly all year, though somewhat less in summer than at other times. The main season in the Bahamas and in Florida is May through July. The fruiting period varies in different parts of India. In South India, blooming usually occurs in January, with fruit ripening in March and April, whereas in the Circars, ripening takes place in April and May. In the central part of the country, flowering occurs in February, March and April and the fruits ripen from June through July. Then again, it is reported that there are varieties that produce fruit in February and March.
In India, they say that a mature rose apple tree will yield 5 lbs (2 kg) of fruit each season. The fruits are, of course, very light in weight because they are hollow, but this is a very small return for a tree that occupies so much space.
Rose apples bruise easily and are highly perishable. They must be freshly picked to be crisp. Some studies of respiration rate and ethylene production in storage have been made in Hawaii. The fruit is non-climacteric.
Pests and Diseases
The rose apple tree has few insect enemies. In humid climates, the leaves are often coated with sooty mold growing on the honeydew excreted by aphids. They are also prone to leaf spot caused by Cercospora sp., Gloeosporium sp., and Phyllosticta eugeniae; algal leaf spot (Cephaleuros virescens); black leaf spot (Asterinella puiggarii); and anthracnose (Glomerella cingulata). Root rot caused by Fusarium sp., and mushroom root rot (Armillariella (Clitocybe) tabescens) attack the tree.
Around the tropical world, rose apples are mostly eaten out-of-hand by children. They are seldom marketed. In the home, they are sometimes stewed with some sugar and served as dessert. Culinary experimenters have devised other modes of using the cuplike halved fruits. One stuffs them with a rice-and-meat mixture, covers them with a tomato sauce seasoned with minced garlic, and bakes them for about 20 minutes. Possible variations are limitless. The fruit is made into jam or jelly with lemon juice added, or more frequently preserved in combination with other fruits of more pronounced flavor. It is also made into a sirup for use as a sauce or to flavor cold drinks. In Jamaica, the halved or sliced fruits are candied by stewing them in very heavy sugar sirup with cinnamon.
Food Value Per 100 g of Edible Portion*
|Ascorbic Acid||3-37 mg|
*Analyses made in Central America and elsewhere.
The seeds are said to be poisonous. An unknown amount of hydrocyanic acid has been reported in the roots, stems and leaves. An alkaloid, jambosine, has been found in the bark of the tree and of the roots, and the roots are considered poisonous.
Fruit: In 1849, it was announced in Bengal that the ripe fruits, with seeds removed, could be distilled 4 times to make a "rosewater" equal to the best obtained from rose petals.
Branches: The flexible branches have been employed in Puerto Rico to make hoops for large sugar casks, and also are valued for weaving large baskets.
Bark: The bark has been used for tanning and yields a brown dye.
Wood: The sapwood is white. The heartwood is dark-red or brown, fibrous, close-grained, medium-heavy to heavy, strong; and has been used to make furniture, spokes for wheels, arms for easy chairs, knees for all kinds of boats, beams for construction, frames for musical instruments (violins, guitars, etc.), and packing cases. It is also popular for general turnery. It is not durable in the ground and is prone to attack by drywood termites.
The tree grows back rapidly after cutting to a stump and consequently yields a continuous supply of small wood for fuel. Rose apple wood makes very good charcoal.
Leaves: A yellow essential oil, distilled from the leaves, contains, among other properties, 26.84% dl-a-pinene and 23.84% l-limonene, and can be resorted to as a source of these elements for use in the perfume industry.
Flowers: The flowers are a rich source of nectar for honeybees and the honey is a good amber color. Much comes from the San Cristobal River Valley in Cuba.
Medicinal Uses: In India, the fruit is regarded as a tonic for the brain and liver. An infusion of the fruit acts as a diuretic.
A sweetened preparation of the flowers is believed to reduce fever. The seeds are employed against diarrhea, dysentery and catarrh. In Nicaragua, it has been claimed that an infusion of roasted, powdered seeds is beneficial to diabetics. They say in Colombia that the seeds have an anesthetic property.
The leaf decoction is applied to sore eyes, also serves as a diuretic and expectorant and treatment for rheumatism. The juice of macerated leaves is taken as a febrifuge. Powdered leaves have been rubbed on the bodies of smallpox patients for the cooling effect.
The bark contains 7-12.4% tannin. It is emetic and cathartic. The decoction is administered to relieve asthma, bronchitis and hoarseness. Cuban people believe that the root is an effective remedy for epilepsy.