Averrhoa carambola

Averrhoa carambola is a species of tree in the family Oxalidaceae native to tropical Southeast Asia; it has a number of common names, including carambola, star fruit and five-corner. It is a small tree or shrub that grows 5 to 12 m (16 to 39 ft) tall, with rose to red-purple flowers. The flowers are small and bell-shaped, with five petals that have whitish edges. The flowers are often produced year round under tropical conditions. The tree is cultivated in tropical and semitropical regions for its edible fruits.

Description

A small evergreen tree up to 6-12 m high. The trunk of the tree is short and crooked and has branches near the base. The bark is smooth and dark grey. A leaf is made up of 2 to 11 leaflets with a leaflet at the end. The leaves are darker and more shiny on the top surface. The flowers are small (8 mm long) and red and white in clusters on the small branches. The fruit are star shaped with five or six angled ridges. They are yellow and up to 16 cm long and 9 cm wide. The flesh is white. There are one or two shiny light brown seeds about 1 cm long, in the bottom of each lobe. Some carambola have short styles (female flower parts) and these types need to be cross pollinated by insects. This means two types need planting. Long style types can fertilise themselves. Fruit flavour can vary from very acid to very sweet. There are several named cultivated varieties.

Edible Uses

Edible Parts: Flowers Fruit Leaves Edible Uses: Condiment Edible portion: Fruit, Flowers, Leaves. Fruit - raw. The fruit is crisp and juicy with a waxy yellow skin when ripe. The best forms are delicious on their own, they also go very well in fruit salads, juiced and mixed with other fruits etc. The fruit flavour is enhanced by peeling off the 'wing' edges, which removes most of the oxalic acid. A quince-like fragrance. Plants can produce fruit all year round. Fruit quality is variable, though they are normally juicy. Sour forms, and slightly immature fruits, are pickled or made into a relish. The orange-yellow fruit is a large, indehiscent berry, 5-8 cm long with a characteristic shape in cross-section resembling a 5-pointed star. The fruit is up to 12.5cm x 6cm. Flowers - raw. An acid flavour, they are added to salads. They can also be made into conserves. Leaves - raw or cooked. An acid flavour, they are used as a sorrel substitute.

Traditional Uses

Fruit can be eaten raw or used for drinks. They are used in curries. They can be used for souring dishes. They are also used for jams, jellies, preserves and pickles. (They are also useful for cleaning brass.) The acid flowers are eaten in salads or made into conserves. Leaves have been eaten as a substitute for sorrel. They can be eaten with coconut milk sauce. CAUTION The fruit contain soluble oxalates.

Medicinal Uses

Abortifacient Antiasthmatic Antirheumatic Antitussive Emmenagogue Febrifuge Galactogogue Hypotensive Skin The fruit can be a laxative on account of the oxalic acid it contains. It is also used in traditional medicine for skin disorders and fevers. It is valued by Chinese communities as a remedy for high blood pressure, whilst it is also said to reduce blood sugar levels and so is of help to diabetics. The flowers are used to relieve coughs. The leaves are used to treat rheumatism. The seed is emmenagogue, galactagogue and abortifacient. The powdered seed is a good anodyne for treating asthma, colic and jaundice.

Known Hazards

Like several other plants of the family Oxalidaceae, its fruits are rich in oxalic acid, which is toxic in high concentrations. There have been reports of intoxication in dialysis and uremic patients caused by a neurotoxin called caramboxin present in the fruit. Such toxin is normally filtered by the kidneys, but patients in dialysis or suffering from kidney deficiencies may show severe symptoms, in a few cases fatal, after drinking the fruit juice.

Distribution

A tropical plant. Five corners need a warm tropical climate so they are mostly seen in the coastal lowlands below about 500m altitude. They will grow up to 1200m in the equatorial tropics. Mature trees can tolerate slight frost. Five corner can grow on several different types of soil. The soil should be well drained. It will grow on alkaline soils but is better in acid soils. Plants cannot stand water-logging. It is suited to moist places but performs better in areas where there is some dry season rather than in places with heavy, constant rain. Trees are fairly wind resistant providing the winds are not cold. Trees are stressed by temperatures near 0°C as well as above 37°C. It grows in Nepal to about 300 m altitude. In XTBG Yunnan. It suits hardiness zones 10-12.

Where It Grows

Africa, Amazon, Andamans, Asia, Australia, Bangladesh, Barbados, Bhutan, Bolivia, Brazil, Burkina Faso, Cambodia, Cameroon, Central Africa, Central America, China, Colombia, Congo DR, Cook Islands, Costa Rica, Cuba, Dominican Republic, East Africa, East Timor, Ecuador, El Salvador, Fiji, Ghana, Grenada, Guam, Guyana, Haiti, Hawaii, Himalayas, India, Indochina, Indonesia*, Japan, Jamaica, Laos, Liberia, Malaysia*, Maldives, Mariana Islands, Marquesas, Mauritius, Mexico, Micronesia, Mozambique, Myanmar, Nepal, New Zealand, Nicaragua, North America, Northeastern India, Pacific, Pakistan, Palau, Papua New Guinea, PNG, Peru, Philippines, Pohnpei, Puerto Rico, Sao Tome and Principe, SE Asia, Slovenia, Solomon Islands, South America, Sri Lanka*, St. Vincent and Grenadines, Suriname, Taiwan, Tanzania, Thailand, Timor-Leste, Tonga, Uganda, USA, Vanuatu, Vietnam, West Africa, West Indies, Yap,

Cultivation

Plants grow best in the hot humid tropics up to an elevation of around 1,200 metres, though they will tolerate some cool weather and can be grown in subtropical areas. It grows best in areas where annual daytime temperatures are within the range 24 - 30°c, but can tolerate 5 - 39°c. Mature plants can be killed by temperatures of -2°c or lower, although young growth is badly damaged at -1°c. It prefers a mean annual rainfall in the range 1,200 - 2,000mm, but tolerates 600 - 3,000mm. Prefers a position with some shade. Prefers a well-drained soil, plants are intolerant of water-logging. Plants are tolerant of a wide range of soils so long as they are slightly acid. This somewhat contradicts the reports that the plant prefers a pH in the range 5.5 - 6.5, tolerating 5 - 8.5. Requires a position sheltered from strong winds. Plants can tolerate dry periods and some wind if it is not too cold. When young, the carambola is delicate and requires careful attention. Because it is a fast-growing tree, it requires pruning and thinning of excess fruit at an early stage. Flowering continues throughout the year and fruit is available most of the year. The fruit can be very variable when plants are grown from seed, with the best forms being large and sweet and others being small and tart. Three crops per year can be obtained. Seedling varieties should start to crop in 3 - 8 years, whilst selected grafted varieties can start in only 1-2 years. Plants can crop prodigiously, and yields of up to 900 kg/year are common for 10-year-old trees. There are many named varieties. Some Brazilian cultivars have a very high content of vitamin C as well as an applicable amount of provitamin A. Production: Seedling trees fruit after 4-5 years. They can produce 400 fruit per tree. Flowers open after 14-21 days and fruit mature after 14-15 weeks. Trees live for a long time and some fruit is produced at most times of the year. Flowers and fruit can be found on the tree at most times, although there is often 2 or 3 main flushes of flowering and fruiting. Fruiting tends to be seasonal about March to May in the southern hemisphere. The tree does not require pruning or any special care once established. Flowers are cross pollinated by bees, flies and other insects. Hand pollination does not help fruit set much. Fruit once ripe will keep for 7-20 days but can be stored longer at 12°C.

Propagation

Seed - sow in a nursery seedbed and transplant into individual containers when large enough to handle. Seeds are planted in a seed bed and planted out when 15-20 cm high. They should be ready to plant out when around 6 - 12 months old. The seed has limited viability. Cool temperatures damage the seeds. Viability can be maintained for 6 months with partially dried seeds at 5°c. Because seeds are produced by cross pollination, variation is common. It is therefore better to use budding or grafting. Taking buds off good trees, or grafting twigs from them, onto 1 year old seedling roots, is the commonest method. Greenwood cuttings Budding on to 12 month old seedlings Grafting Layering. This method can produce fruiting plants within 10 months. Marcottage or air layering can also be used, although it is difficult. A spacing of 6 m x 6 m is suitable. Trees need to be grafted if sweeter kinds of fruit are to be selected.

Other Uses

Dye Fuel Mordant Rust Wood Other uses rating: Low (2/5). Backyard tree, Small flowering tree, large container tree, Courtyard, Large conservatory. Other Uses In some countries, the fruit juice is used to remove stains, for example iron rust from linen cloth. It can also be used for polishing brass. The fresh juice is an effective stain remover. Unripe fruits contain potassium oxalate, which is used in dyeing. The whitish wood is soft. Generally only available in small dimensions, it is sometimes used for timber in construction and for making small implements, furniture etc. The wood is a suitable candidate for firewood. Special Uses Food Forest

Production

Seedling trees fruit after 4-5 years. They can produce 400 fruit per tree. Flowers open after 14-21 days and fruit mature after 14-15 weeks. Trees live for a long time and some fruit is produced at most times of the year. Flowers and fruit can be found on the tree at most times, although there is often 2 or 3 main flushes of flowering and fruiting. Fruiting tends to be seasonal about March to May in the southern hemisphere. The tree does not require pruning or any special care once established. Flowers are cross pollinated by bees, flies and other insects. Hand pollination does not help fruit set much. Fruit once ripe will keep for 7-20 days but can be stored longer at 12°C.

Other Information

Trees are moderately common in coastal areas of Papua New Guinea. Types vary in their sweetness. They are sold in local and global markets. It is cultivated.

Notes

There are 5 Averrhoa species. It contains 29.25 mg alpha-tocopherol (Vitamin E) per 100 g in the leaves.

Nutrition

Synonyms

Also Known As

Amrak, Ansu, Balimbieng manih, Balimbing, Balingbing, Belimbing manis, Belimbing sagi, Bikembines, Blimbing alas, Calingcing amis, Camaranga, Cambaranka, Coromandel, Dusma tahpla, Five-cornered fruit, Fivesider, Fransman birambi, Fuang, Hainijom, Kaamaranga, Kamarakh, Kamaranga, Kamrakh, Kamranga, Kamrenga, Kam rangthai, Kandasagadam, Karambola, Kardoi, Khamrak, Khe, Kordoi, Ma fueang, Ma-fueng, Mafen, Mafuang, Mak fu yang, Mak-hpung, Moyabo, Paka paka, Sisam, Sonosambal, Spo, Spu, Star Fruit, Thei-helh-hot, Torte, Wi ni Idia, Zaung-yar

References (165)

• Carambola or Five corner references
• AAK, 1980, Bertanam Pohon Buah-buahan. Penerbitan Yayasan Kanisius, Jogyakarta. p 15
• Abbiw, D.K., 1990, Useful Plants of Ghana. West African uses of wild and cultivated plants. Intermediate Technology Publications and the Royal Botanic Gardens, Kew. p 42
• Alexander, D.M., Scholefield, P.B., Frodsham, A., 1982, Some tree fruits for tropical Australia. CSIRO, Australia. p 15
• Allen , B.M., 1975, Common Malaysian fruits. Longmans p 31.

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