Averrhoa carambola
| Carambola (Averrhoa carambola) | |
|---|---|
 | |
| Scientific name | Averrhoa carambola L. |
| Common names | Carambola, star fruit, starfruit, five-finger |
| Genus | Averrhoa |
| Family | Oxalidaceae |
| Order | Oxalidales |
| Native range | Southeast Asia; cultivated widely in tropical and warm-subtropical regions |
| Growth form | Fast-growing, evergreen, single- or multi-trunked small to medium tree |
| Mature size | About 7–10 m tall and 6–7.6 m wide in the UF/IFAS landscape account |
| Climate and site | Warm to hot tropical or warm-subtropical site; full sun, moisture, free drainage, and wind protection |
| Soil and water | Many well-drained soils; best at pH 4.5–7; drought-sensitive and intolerant of salinity |
| Propagation | Fresh seed; grafting or budding for named cultivars |
| Years to fruit | About 10–14 months after planting reported for protected Florida trees; seedling and cultivar timing varies |
| Pollination | Heterostylous; some cultivars set well alone, while others benefit from a contrasting stylar type |
| Fruit and harvest | Yellow, waxy, 5-ribbed berry; about 60–75 days from set to maturity |
Carambola (Averrhoa carambola L.), also called star fruit or starfruit, is a fast-growing evergreen tree in the Oxalidaceae. Its yellow, longitudinally ridged fruit has a five-pointed star cross-section. The species is native to Southeast Asia and is now cultivated through many tropical and warm-subtropical regions.[1]
Description
Carambola is usually a single- or multi-trunked tree with a spreading crown. The UF/IFAS account describes mature trees about 7–10 m tall and 6–7.6 m wide in landscape conditions, although pruning and site quality change the final size. The compound leaves are arranged alternately and have 5–12 leaflets. In cooler locations, an evergreen tree may lose some or all of its leaves in late winter or early spring.[1]
Small, pink to lavender, perfect flowers are borne in panicles on twigs and sometimes on older wood. The fruit is a fleshy berry with a thin, waxy skin and usually five prominent ribs. Ripe fruit may be light to dark yellow, with crisp, translucent, juicy flesh and a subacid to sweet flavor. Fruit size in the UF/IFAS description ranges from about 5–15 cm long; some fruits contain few seeds or none.[1]
Distribution and habitat
UF/IFAS gives Southeast Asia as the origin and records centuries of cultivation in places including Malaysia, India, and Sri Lanka. The crop is now grown in tropical and warm-subtropical areas worldwide; in the United States, commercial production is concentrated in southern Florida and Hawaii.[1]
The available cultivation sources describe carambola chiefly in warm, moisture-available lowland settings rather than one narrowly defined native soil. That limitation matters when translating the crop to a different climate: the tree needs regular root-zone moisture, but the soil must still drain and remain aerated.
Cultivation
Carambola grows best with warmth, full sun, continuous access to soil moisture, and protection from persistent wind. It is not a reliably hardy outdoor tree in climates with regular freezes. Best growth and fruiting are reported at about 20–35 °C (68–95 °F); growth generally slows below 18 °C (65 °F). Young leaves can be killed near 30–32 °F, while severe damage or death becomes increasingly likely as temperatures fall through the upper 20s and lower 20s °F.[1]
Soil and water
The species tolerates many well-drained soil types and performs best in moderately acid to neutral soil, approximately pH 4.5–7 in the UF/IFAS guidance. High-pH or calcareous soils can induce iron, manganese, magnesium, and zinc deficiencies. Correcting those problems requires site-specific micronutrient management rather than assuming that extra irrigation will solve them.[1]
Carambola has limited drought tolerance. During drought, leaves may fold, wilt, yellow, or drop, with reduced flowering and smaller fruit. It can tolerate short periods of flooding, reported as roughly 2–10 days depending on tree health and temperature, but prolonged saturation stops growth and increases the risk of root disease. On a wet site, plant on a raised mound or choose a better-drained position.[1]
Sun and humidity
Use full sun for the best growth and fruit production. Warm, humid air suits the species, but shelter from constant wind is important: wind can scar fruit, reduce fruit size and yield, and cause leaf and stem damage. Leave enough spacing for airflow and avoid a stagnant, enclosed canopy.[1]
Seasonal changes
Carambola may flower sporadically throughout the year in warm climates, but the UF/IFAS Florida calendar has two major bloom periods, April–May and September–October. Its main harvest period there is June through February, with production peaks in August–September and December–February; local wet/dry cycles, temperature, cultivar, and pruning can shift these dates.[1]
Keep young trees evenly watered while establishing. Once a tree bears, maintain irrigation from flowering through harvest, especially during a dry season. In a cool subtropical climate, reduce expectations during winter: cool temperatures slow growth, and cold injury can remove the current crop even if the tree survives.
Propagation
Fresh seed is viable only briefly: UF/IFAS reports that seeds lose viability within a few days after removal from the fruit. Seedlings are useful for rootstocks and for trial plants, but fruit quality and maturity can vary among seedlings. Useful Tropical Plants reports seedling cropping in roughly 3–8 years, while selected grafted plants may begin in 1–2 years; the UF/IFAS Florida account reports fruiting within 10–14 months after planting for wind-protected trees. These figures come from different sources and production contexts, so none should be treated as a universal schedule.[1][2]
Named cultivars are generally grafted onto seedling rootstocks. UF/IFAS reports good results from veneer grafting and chip budding during active growth. Air-layering has not proved successful in the cited guidance because of poor root development.[1]
Flowering, fruiting, and harvest
Carambola flowers are heterostylous: flowers of a given cultivar generally have either long or short styles. Some cultivars, including 'Fwang Tung', 'Golden Star', and 'Arkin', can produce abundant crops in solid blocks, while 'B-10' and 'B-17' are reported to fruit more heavily when pollinated with another variety. A second cultivar with the contrasting stylar type can therefore be useful, but cross-pollination should not be stated as mandatory for every carambola.[1]
In the UF/IFAS Florida account, fruit matures about 60–75 days after fruit set. Fruit may be harvested when yellow and allowed to finish ripening, but it is sweetest when fully tree-ripened. Handle the thin-skinned fruit carefully because bruising and rapid quality loss limit storage and shipping. Wind-protected trees may carry a few fruits through much of the year in suitable climates.[1]
Fruit and uses
Ripe carambola is eaten fresh, juiced, added to fruit salads, or used in preserves and cooked dishes. Sweet cultivars are generally preferred for fresh eating, while sweet and tart types can both be useful in recipes. Seed content ranges from several seeds to none, depending on the cultivar and fruit.[1][2]
People with kidney disease should not eat carambola unless their clinician has specifically said it is safe. UF/IFAS notes that the fruit may contain enough oxalic acid to cause a rapid decline in renal function in people with kidney disease; this is a food-safety limitation, not a general claim that the fruit is unsafe for everyone.[1]
Pests and diseases
UF/IFAS reports scale insects, diaprepes weevil, stink bugs, squash bugs, fruit blotch miner, and fungal fruit rots among possible problems. Drought, salinity, wind, high-pH micronutrient deficiencies, flooding, and mechanical trunk injury can also reduce vigor or crop quality. Good drainage, wind protection, careful irrigation, and a grass-free zone around the trunk address several of these stresses; current controls should follow local extension recommendations.[1]
Photos
References
- [1] Crane, J. H. Carambola Growing in the Florida Home Landscape, UF/IFAS Extension publication HS12/MG269, accessed 2026-08-24.
- [2] Useful Tropical Plants: Averrhoa carambola, Tropical Plants Database, accessed 2026-08-24.
Image credits
- Carambola Starfruit.jpg — SMasters; CC BY-SA 3.0. Whole and cut fruit are shown, including the star-shaped cross-section.
