IN THE ARBORETUM TODAY
By Alfredo Chiri
The Carambola, commonly called Starfruit because of the shape of the fruit when sliced, is believed to have originated in Ceylon and has been grown in Southeast Asia and Malaysia for many years.
It is a slow-growing tree with bushy, branched crown. The leaves are soft, medium green, smooth on the upper surface, and with fine hairs on the underside. The leaves are sensitive to light and are inclined to fold together at night or when the tree is shaken or abruptly shocked.
Small clusters of red, lilac or purple flowers are borne in clusters on twigs in the axil of the leaves. The 5 or 6 angled fruits are 2 to 6 inches long. They have a thin, waxy skin that is bright yellow-orange. They are crisp and juicy when fully ripe. Slices cut in cross-section form a star.
The flesh of the fruit is light yellow, very juicy, without fiber and has a rusty odor. The flavor can range from sour to mildly sweet. The fruits that are considered sweet have a very low sugar content. The fruit may contain thin brown seeds or none at all. The seeds lose their viability few days after they have been removed from the fruit.
Carambolas do best in a frost-free location, needing full sun and regular watering during the summer months and winter dry spells. Moisture improves their fruit production. The tree is prone to chlorosis but responds well to soil and foliar application of chelated iron.
Carambolas seldom need pruning. Topping the tree stimulates growth of the lateral branches (auxin influence).
The Carambola is widely grown from seed. The viability of the seed is lost in a few days after it has been removed from the fruit. Therefore only the most fully developed seeds should be used. Healthy year-old seedlings are best for rootstocks. Grafting to seedlings is done by using mature scions whose leaves are still present or where the buds are beginning to grow.
A rule of thumb in testing for the best seeds: In a glass, add warm water and then add the seeds. Those that have not developed will tend to float, and those fully developed will sink to the bottom of the glass.
CARAMBOLA - Averrhoa carambola var. Arkin - Oxalidaceae
Donated by: CRFG and planted in 1989 (r.f.-02)
Common names: carambola, starfruit, caramboleira