Fwang Tung Starfruit (Averrhoa carambola)
Starfruit is one of those trees that feels like a “tropical upgrade” the first time you see it fruiting. The branches hang with glossy, ribbed fruit that slice into perfect stars, and the tree itself stays tidy enough to feel at home in a backyard food forest when it’s pruned with intention.
Fwang Tung is a well-loved carambola selection for warm climates, prized for reliable production and sweet-tart flavor when harvested at the right stage. The trick is timing: fruit picked too green tastes sharp, while fruit allowed to turn mostly yellow becomes far more balanced and dessert-friendly.
In Florida planting zone 9, starfruit is best treated like a “protected tropical.” Give it sun, moisture, organic matter, and a warm microclimate out of cold wind. With that setup, it can reward you with heavy crops and that unmistakable star-shaped harvest that makes every bowl look fancy.
Any reference to medicinal or culinary use of plants or plant parts should in no way be considered an endorsement by The Ocala Food Forest or its staff. Research is crucial in safe and proper consumption or experimentational use of any plant.
Plant Information
| Scientific Name: | Averrhoa carambola (cultivar commonly sold as “Fwang Tung”) |
|---|---|
| Family Name: | Oxalidaceae (Oxalis / wood-sorrel family) |
| Common Name(s): | Starfruit, Carambola, Fwang Tung Starfruit |
| Size: | Typically 10–25 ft in cultivation (often kept 8–12 ft with pruning); spreading canopy |
| Plant Type: | Evergreen to semi-evergreen tropical fruit tree |
| Origin/Geographic Distribution: | Native to tropical Southeast Asia; cultivated in tropical/subtropical regions worldwide |
| Native to: | Tropical Southeast Asia |
| Planted range in the USA: | Most successful in South Florida and other frost-limited areas; grown in protected microclimates or containers farther north |
| Conservation Status: | Not listed as threatened or endangered (cultivated fruit tree) |
Cultivation
| Planting: | Plant in spring after the last cold snaps so roots establish before winter; avoid low pockets where cold settles |
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| Sun Exposure: | Full sun for best flowering and fruiting; light afternoon shade is fine in very hot, reflective sites |
| Soil Type: | Well-drained loam/sandy loam enriched with compost; avoid chronic wet feet |
| Soil pH: | 5.5 to 6.5 (slightly acidic preferred; can tolerate near-neutral with micronutrient support) |
| Water Requirements: | Moderate to high; keep evenly moist during flowering/fruit fill—mulch heavily to stabilize moisture |
| Fertilizer Requirements: | Moderate; feed during the warm growing season with a balanced fruit-tree fertilizer and micronutrients as needed (iron/manganese issues can show in high pH soils). |
| Pruning Requirements: | Prune to keep a compact canopy and encourage airflow; tip-prune after harvest to maintain height and branching |
| Growth Rate: | Medium to fast in warm weather with steady moisture (often 1–3 ft/year once established) |
| Companion Planting: | Best companions are living mulches and nitrogen-fixers that build soil without competing tightly at the trunk |
Tolerance and Hardiness
| Drought Tolerance: | Low to moderate; drought stress reduces flowering and causes fruit drop—consistent moisture is key |
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| Frost Tolerance: | Low; leaf damage often begins near 32°F (0°C). Severe damage around 30°F (−1°C). Trees can be killed near 27°F (−3°C), especially if freeze is prolonged |
| Heat Tolerance: | High; handles 100°F (38°C) well with irrigation. Above 105°F (41°C) may cause stress/sunscald if dry or reflective |
| Wind Tolerance: | Low to moderate; flowers and fruit can drop in strong winds—use windbreaks for better set |
| Salt Tolerance: | Low to moderate; avoid direct salt spray and salty irrigation |
| USDA Plant Hardiness Zones: | Typically 10–11 (best). Can be grown in 9 with a warm microclimate + freeze protection |
Flower and Fruit Information
| Fruit Type: | Fleshy fruit with 5 prominent ribs (slices form a star shape) |
|---|---|
| Harvest Time: | Warm-season to fall (often multiple flushes in warm climates). Harvest when the fruit turns mostly yellow with only a hint of green along the ridges |
| Fruit Description: | Crisp, juicy flesh; flavor ranges from sweet-tart to sweeter depending on ripeness and growing conditions |
| Edible Plant: | Yes (fruit) |
| Edible Parts: | Fruit flesh (skin is also typically edible when clean and pesticide-free) |
| Medicinal: | Not a primary medicinal plant in a home-garden context; focus is culinary fruit use (see Health & Safety note for kidney concerns) |
| Flower Color: | Pink to lavender (small clusters) |
| Flower Shape: | Small, starry blossoms in clusters along young branches |
| Fragrance: | Light to mild |
| Flower Bloom Time: | Warm season (often in waves) |
| Bloom Duration: | Cycles of bloom can occur over weeks; fruit develops after successful set |
| Pollination: Self or Other? | Often self-fertile, but insect activity and nearby trees can improve fruit set and yield |
Wildlife
| Attracts: | Bees and beneficial insects during bloom; ripe fruit can attract birds and other wildlife if left on the tree |
|---|---|
| Pollinators: | Bees and other small insects that work flower clusters |
| Problematic Pest: | Fruit flies (in some areas), scale insects, aphids, mealybugs, and mites; birds may peck ripe fruit. |
Health and Safety
| Toxic: | Not typically toxic for healthy individuals; however, starfruit is high in oxalates and contains compounds that can be dangerous for people with kidney disease |
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| Poisonous Parts of Plant: | No commonly recognized “poisonous” plant parts for casual landscape contact; fruit safety depends on human health factors |
| Toxic to Humans: | People with kidney disease or kidney impairment should avoid starfruit (serious reactions have been reported). For others, treat as a normal food and consume in moderation |
| Toxic to Animals: | Not commonly listed as toxic to pets; avoid letting pets binge on large amounts of fruit due to sugar/acid and potential stomach upset |
| Plant Diseases to be aware of: | Anthracnose, leaf spot, algal leaf spot, fruit rots, and root rot in poorly drained soils |
Companion Planting
For Fwang Tung Starfruit (Averrhoa carambola), the best companions are plants that build soil, hold moisture, and attract beneficial insects—without competing hard at the trunk. Keep a clear mulched ring around the base of the tree, then use living mulch and supportive plants outside that ring.
Florida Native: Sunshine Mimosa (Mimosa strigillosa)
Zone Range: 8–11
Benefits: Nitrogen-fixing groundcover that supports pollinators and helps suppress weeds.
Use: Use as living mulch outside the trunk’s clear mulch ring; mow/trim to keep it tidy.
Florida Native: Frogfruit (Phyla nodiflora)
Zone Range: 7–11
Benefits: Tough living mulch that reduces soil splash and feeds pollinators.
Use: Let it fill pathways/edges around the tree—excellent where you want low maintenance.
Florida Native: Beautyberry (Callicarpa americana)
Zone Range: 6–10
Benefits: Wildlife value and biodiversity; can help buffer wind at the orchard edge.
Use: Plant as a perimeter shrub so it doesn’t shade the starfruit canopy too much.
Florida Friendly: Perennial Peanut (Arachis glabrata)
Zone Range: 8–11
Benefits: Nitrogen-fixing, low groundcover that suppresses weeds and stabilizes moisture.
Use: Use as a “mulch replacement” groundcover outside the trunk ring; great under open-canopy trees.
Florida Friendly: Pigeon Pea (Cajanus cajan)
Zone Range: 9–11 (often grown as an annual in cooler zones)
Benefits: Nitrogen-fixer and biomass factory; can serve as a temporary nurse plant and wind softener.
Use: Plant on the windward side and chop-and-drop as mulch when it starts to shade the tree.
Florida Friendly: Lemongrass (Cymbopogon citratus)
Zone Range: 9–11
Benefits: Aromatic clumps add mulch material and help define bed edges.
Use: Plant as a border clump; harvest routinely and keep it away from the trunk zone.
Starfruit drops flowers and fruit when stressed. Keep moisture steady, mulch wide, and protect from cold wind. If you’re pushing this tree in zone 9, prioritize a warm wall/microclimate and be ready to cover the canopy on freeze nights.
Sources & References
Reference list used for general horticultural guidance and Florida-relevant best practices (not medical advice):
- UF/IFAS Extension (Solutions for Your Life) — Florida-oriented guidance for home fruit trees, soils, watering, and seasonal care practices.
- UF/IFAS EDIS Publication Database — research-based publications on tropical/subtropical fruit culture and integrated pest management principles.
- Florida-Friendly Landscaping™ Program — water-wise, sustainable landscape practices that pair well with food forest systems.
- USDA Plant Hardiness Zone Map — zone framework reference for planting suitability and winter-risk expectations.
- Kew: Plants of the World Online — authoritative taxonomy and native-range context for Averrhoa species.