Averrhoa carambola
Common Name: star fruit 
Type: Broadleaf evergreen
Family: Oxalidaceae
Native Range: Indonesia, India, Sri Lanka
Zone: 10 to 12
Height: 20.00 to 30.00 feet
Spread: 20.00 to 30.00 feet
Bloom Time: Seasonal bloomer
Bloom Description: Rose
Sun: Full sun
Water: Medium
Maintenance: Low
Flower: Showy, Fragrant
Leaf: Evergreen
Fruit: Showy, Edible
Other: Winter Interest

Culture

Winter hardy to USDA Zones 10-12 where it is best grown in rich, acidic, evenly moist, well-drained loams in full sun. Best sited in locations sheltered from wind. Generally intolerant of frost. In St. Louis, it may be grown in containers that are overwintered indoors, but it may not bear fruit. Plants generally stop active growth when temperatures dip below 55 degrees F.

Noteworthy Characteristics

Averrhoa carambola, commonly called star fruit is a small, slow-growing, short-trunked tropical tree that probably originated in Malaysia, Indonesia and southern China. It now extinct in the wild. It is grown commercially in many tropical and sub-tropical areas around the world for its unusual fruit. It also serves as an attractive, multi-branched ornamental tree. It typically grows to 20-30' tall with a broad rounded crown featuring odd-pinnate, medium green leaves (to 6-10" long). Each leaf has 5-11 ovate to ovate-lanceolate leaflets (to 1.5-3.5" long). Leaflets are sensitive to light and touch, folding up like mimosas in the dark of night or if disturbed. Fragrant rose flowers (1/4" across) bloom in the leaf axils throughout the year, typically in up to four separate flushes. Flowers give way to waxy, oblong/ellipsoidal, 5-angled, orange/yellow-skinned fruits (3-6" long) which are star-shaped when sliced in cross-section, hence the common name. Fruit flesh is juicy and ranges from sour to mildly sweet when ripe. Fruits are typically eaten fresh, combined in salads with other fruits, added to dessert dishes or sliced for use as star-shaped garnishes.

Genus name comes from the fruit trees named after a celebrated Moorish physician and philosopher Ibn-Ruschd known as Averroes (1126-1198) who was born in Cordoba, Spain.

Problems

No serious insect or disease problems. Root rot may develop in overly moist soils. Anthracnose, leaf spots and sooty mold may also occur. Potential insect pests include fruit flies, beetles, caterpillars, nematodes, scale and stinkbugs.

Garden Uses

Fruit tree or small ornamental shade tree for frost free areas. Interesting container plant for colder areas. Bonsai.