Averrhoa carambola or Star Fruit is a tree native to tropical Asia.
It’s a nice, fast growing tree that produces many flowers and fruit after 5 years.
The leaves close during the night, in the absence of light, and in case of shock to the plant.
The fruits are acidic or sweet sour. Some varieties contain too much oxalic acid for patients with kidney problems.
It is not frost resistant but can be grown as a houseplant and placed outside in the summer.
It is a small tree of 5-12 m high. The trunk is relatively short with drooping branches that form a broad, rounded crown.
The leaves are composed and green, 15-20 cm long. The leaflets are 4-9 cm long, oval or oblong, smooth on top and covered with fine white hairs underneath. They are light sensitive and folding at night, as well as in case of shock or shake of the plant. Prolonged drought the leaves fall off.
The flowers are pink to violet, downy and are produced in the axils of the leaves at the end of twigs, in small clusters. Each flower is about 6 mm wide, with 5 recurved petals. Flowers year round in the tropics.
The fruits are striking: they are elongated and have 5 to 6 ribs so that the cross section looks like a star. They are up to 15 cm long and 9 cm wide. The skin is thin, orange-yellow and waxy. The fruits are juicy and yellow inside, they smell of oxalic acid. Depending on the kind of the variety, the fruit contains more or less acid, more or less sugar.
Each fruit contains up to twelve 6 to 12.5 mm long, thin and brown seeds. Some of the cultivated varieties produce fruit without seeds.
Balimbing, Carambola, Coromandel Gooseberry, Five Fingers, Five-Corner Fruit, Five-Finger, Honey Starfruit, Star Apple, Star Fruit, Starfruit
Averrhoa: named after Averrhoes (1126-98), an Arab philosopher.
Carambola: is said to be derived from the Malabar and adopted by the Portuguese.
Warm, hot tropics, between 0-900 m altitude.
USDA zone 10-11, -3 °C. Young plants do not tolerate frost, older plants can tolerate down to -3 °C but there will be damage to branches and leaves.
Prefers deep, well drained clay loam, but can successfully grow on sandy soils and heavy clay
During growing season, universal liquid fertilizer weekly or bi-weekly
Ideal temperature: 20-35 °C, below 18 °C, growth stops
Seed, cuttings or grafting. Sowing is very easy but in agriculture grafted specimens produce better offspring with better fruit.
- due to the low viability of the seeds, they must be sown directly after harvesting
- sowing in light, moist soil
- wrap the pot to prevent evaporation of water
- germination time: 5-7 days in summer, 12-18 days in winter
- protect the seedlings against wind