Carambola or Star Fruit
The Carambola or Star Fruit is an unique and flavorful fruit. The fruit’s flavor ranges from very sour to mildly sweetish and tastes something like a mix of apple, pineapple, and kiwi fruit. Slices cut in cross-section have the form of a star.
The carambola tree is medium fast growing, has a short-trunk, is multi-branched, bushy, broad, with a rounded crown and reaches 20 to 30′ in height and about the same in width. Pruning will keep the tree from getting too large while still allowing it to bear fruit prolifically. A good tropical fruit tree for limited space.
Common Name: Star Fruit, Carambola
Botanical Name: Averrhoa carambola
Plant Type: Deciduous tree
Origin: Ceylon and the Moluccas
Zones: 8 (in sheltered areas) – 11
Height: to 30′
Rate of Growth: Slow
Salt Tolerance: Low
Soil Requirements: Not too particular as to soil, but will grow faster and bear more heavily in rich loam. Needs good drainage; cannot stand flooding.
Water Requirements: Medium drought tolerance
Nutritional Requirements: Balanced liquid fertilizer monthly, side dressings of composted manure
Light Requirements: Full sun
Form: Short-trunk with a much-branched, bushy, broad, rounded crown
Leaves: Deciduous leaves, spirally arranged, are alternate, imparipinnate, 6 to 10″ long, with 5 to 11 nearly opposite leaflets, ovate or ovate-oblong, 1 1/2 to 3 1/2″ long; soft, medium-green, and smooth on the upper surface, finely hairy and whitish on the underside. The leaflets are sensitive to light and more or less inclined to fold together at night or when the tree is shaken or abruptly shocked.
Flowers: Small clusters of red-stalked, lilac, purple-streaked, downy flowers, about 1/4″ wide, are borne on the twigs in the axils of the leaves.
Fruits: Showy, oblong, longitudinally 5- to 6-angled fruits, 2 1/2 to 6″ long and up to 3 1/2″ wide, have thin, waxy, orange-yellow skin and juicy, crisp, yellow flesh when fully ripe. Slices cut in cross-section have the form of a star. Flavor ranges from very sour to mildly sweetish. May be up to 12 flat, thin, brown seeds 1/4 to 1/2″ long, or none at all.
Pests or diseases: Fruit flies, black beetles, stinkbugs, nematodes, anthracnose, leaf spot, and sooty mold.
Uses: Accent tree, the fruits have been used as “conversation pieces”.
Cost: $$ — Very reasonable
Propagation: Cuttings, air-layering, or seeds
Sources: Morton, J. 1987. Carambola. p. 125–128. In: Fruits of Warm Climates. Julia F. Morton, Miami, FL.; Carambola Growing in the Florida Home Landscape, document HS12, Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date April 1994. Revised May 2007, Jonathan H. Crane