A star fruit tree (carambola, Averrhoa carambola) is a small tropical evergreen that bears ribbed, waxy yellow fruit which forms a star when sliced. In warm, nearly frost-free climates it can fruit within about a year of planting, and home trees are pruned to stay about 6 to 12 feet tall. Pick star fruit when the green along the ribs turns yellow. Because star fruit contains oxalic acid and other compounds that damaged kidneys cannot clear, people with kidney disease should not eat it. This guide covers where it grows, varieties, planting, care, cold protection, pests, harvest and the health warning.
Star fruit (carambola) quick facts
| Botanical name | Averrhoa carambola (family Oxalidaceae) |
|---|---|
| Other names | Carambola, five-corner fruit |
| Natural height | About 20 to 30 feet tall and 20 to 25 feet wide if unpruned |
| Pruned height | About 6 to 12 feet in home gardens |
| Best growth | 68 to 95°F; growth slows below about 65°F |
| Cold damage | Young growth killed at about 30 to 32°F; large branches and mature trees may die at 20 to 24°F |
| First fruit | As soon as 10 to 14 months after planting a grafted tree |
| Fruit | 2 to 6 inches long, five ribs |
Health warning: Star fruit contains oxalic acid, which in significant amounts can cause kidney problems. The University of Florida (UF/IFAS) advises that people diagnosed with kidney disease should not eat carambola unless their doctor says it is safe, because the fruit may contain enough oxalic acid to cause a rapid decline in kidney function. If you have kidney disease or are on dialysis, avoid star fruit and its juice and ask your doctor. This article is general gardening information, not medical advice.
What is a star fruit tree?
Carambola is native to Southeast Asia and is now grown in tropical and subtropical regions worldwide, including south Florida, Hawaii and Puerto Rico. UF/IFAS says it has been grown in Florida for over 100 years and is produced commercially in Dade, Lee, Broward and Palm Beach counties. The fruit has five (sometimes six) ridges running along its length, so each slice is star-shaped, and the tree is also used as an ornamental in yards. The small flowers are pink to lavender.
Which star fruit varieties should you grow?
There are two types, sweet and tart. UF/IFAS recommends sweet varieties for fresh eating, while tart types are used in cooking and drinks, and notes that tart types may sweeten if left on the tree to ripen further. The UF/IFAS Charlotte County post on starfruit names ‘Arkin’, a Florida-origin sweet variety well suited to backyards, ‘Lara’, ‘Fwang Tung’ and ‘Bell’ as good choices, and the UF/IFAS St. Lucie County article adds that most varieties set fruit without a pollinator, but ‘B-10’ and ‘B-17’ yield more when cross-pollinated. Planting two different cultivars usually improves fruit set.
Where can you grow star fruit?
Star fruit needs warmth. The UF/IFAS St. Lucie County article on growing star fruit reports best growth at 68 to 95°F, slower growth below 65°F, young leaves, young trees and twigs killed at about 30 to 32°F, and large branches and mature trees that may die at 20 to 24°F. In cooler areas the tree may lose some or all of its leaves in late winter and early spring. That makes it a tree for frost-free and nearly frost-free areas, roughly the warmest parts of zone 9b through 11. Check your USDA hardiness zone with the growing zone finder and your frost risk with the frost date tool. In colder areas, grow a grafted carambola in a large container and bring it into a bright, cool room for winter.
Carambola also dislikes strong wind, which tears leaves and knocks off flowers and fruit, and it is not salt tolerant, so it is not ideal for coastal sites. Plant it in a sheltered spot. UF/IFAS notes that trees pruned to 12 feet or less handle windy conditions better.
How big does a star fruit tree get?
Left alone, a carambola can reach about 20 to 30 feet tall and 20 to 25 feet wide. The UF/IFAS Gardening Solutions guide says it responds well to pruning and that light annual pruning can keep a tree near 12 by 12 feet. Home trees are usually pruned to about 6 to 12 feet so the fruit is easy to reach and the tree is easier to cover in cold snaps. Keep unpruned trees 20 to 30 feet from other trees, buildings, structures and power lines.
How to plant a star fruit tree
- Pick a grafted tree. Grafted trees of named varieties fruit sooner and more consistently than seedlings. UF/IFAS says trees are usually grafted onto seedling rootstocks.
- Choose full sun with shelter from wind and good drainage. UF/IFAS says carambola tolerates flooded soil for only about 2 to 10 days, depending on tree health, and recommends planting on a mound 3 to 4 feet high and 4 to 10 feet wide in areas that flood.
- Check the soil. Carambola grows best in well-drained but moist soil. In high-pH, alkaline soils the leaves often turn yellow from iron or manganese deficiency, which may call for micronutrient sprays.
- Dig a wide hole, about three times the width of the root ball, no deeper than the root ball. Use the plant spacing calculator for rows.
- Water deeply and mulch 2 to 4 inches deep, keeping mulch away from the trunk. The mulch calculator shows how much to buy.
How do you care for a carambola tree?
- Water: Carambola is not drought tolerant. UF/IFAS lists wilting, leaf drop, reduced fruit size and limb dieback as drought signs. Water new trees regularly while they establish, and give mature trees regular water between flowering and harvest. Estimate amounts with the garden watering calculator.
- Fertilize: UF/IFAS recommends a mixed fertilizer with nitrogen, phosphorus, potassium and magnesium every 30 to 60 days for young trees, with about ¼ to ½ pound per application, and 4 to 6 applications a year for mature trees. Foliar micronutrient sprays may be needed to prevent deficiencies. See our fruit tree fertilizer guide.
- Prune: Thin crowded branches and cut back tall shoots after harvest to keep the tree low and open.
- Cold protection: Cover small trees and mulch the root zone before frost. Tolerance improves as the tree matures.
How long does it take a star fruit tree to bear fruit?
A grafted carambola can begin bearing as early as 10 to 14 months after planting in favorable conditions. Seedlings take several years and often produce poorer fruit. UF/IFAS says fruit takes about 75 days from set to harvest, and that in Florida the tree blooms in April to May and September to October, with main crops in August to September and December to February, and some cultivars producing two to three crops a year. Production climbs fast: a first- or second-year tree may bear 10 to 40 pounds, a five-year-old tree 100 to 150 pounds, and large mature trees well over 250 pounds a year.
When is star fruit ripe and how do you pick it?
UF/IFAS advises picking carambola when it turns from green to yellow, leaving some green along the ridge tips. Fruit picked at this stage continues to color off the tree, but the fruit is sweetest when fully ripened on the tree. Fully yellow-orange fruit bruises easily, so handle star fruit gently; the ribs bruise and brown quickly. Fresh star fruit keeps about 3 weeks refrigerated. Wash it, trim the brown edges of the ribs and slice crosswise. The thin waxy skin is edible, and each fruit has about a dozen edible seeds, although seeds lose viability within a few days of removal.
Common star fruit tree problems
| Symptom | Likely cause | What to do |
|---|---|---|
| Yellow leaves with green veins | High soil pH, iron or manganese deficiency | Test pH; use chelated micronutrients |
| Flowers drop without fruit | Poor pollination, wind, drought | Add a second cultivar; water steadily |
| Brown, bruised ribs | Rough handling or overripe fruit | Pick earlier; handle gently |
| Holes or larvae in fruit | Fruit flies, fruit moths or fruit blotch miner | Pick promptly; clean up fallen fruit |
| Wilting, decline, poor yield | Pythium root rot or drought | Improve drainage; keep soil evenly moist |
| Cold-burned leaves | Freeze | Cover young trees; delay pruning until damage shows |
UF/IFAS lists scale insects (plumose, philephedra and brown scales), stink bugs, squash bugs, fruit blotch miner, red-banded thrips and diaprepes weevil (root damage) as insect pests, and birds, opossums and raccoons as animals that take fruit. Leaf spots usually do not need control. See scale insects on plants, and use the yellow leaf identifier for leaf symptoms and the pest identifier for insects.
Can you grow star fruit in a pot?
Yes. A grafted tree in a large container with a fast-draining, slightly acidic potting mix can fruit and can be moved indoors in winter. Place it in the sunniest spot you have, protect it from drafts and wind, water regularly (container trees dry out quickly) and feed lightly through the warm season. Prune to keep it compact and bring it inside before temperatures drop below the mid-30s. Use a grow bag or pot of at least 15 to 20 gallons for a mature tree.
How to use star fruit in the kitchen
Star fruit is mild, juicy and slightly tart-sweet, with a crisp texture like a grape crossed with an apple. Slice ripe fruit into stars for fruit salads, garnish drinks and plates, or add it to salsas, stir-fries and curries, where tart types shine. Sweet types make good juice, though anyone with kidney problems should avoid it. Use firm, just-ripe fruit for decorative slices and fully ripe fruit for eating out of hand, and refrigerate the extras. Drying slices in a dehydrator makes chewy, tangy snacks. Freeze whole fruit or slices on a tray for smoothies if you have more than you can eat fresh.
A simple year-round care plan
- Spring: fertilize on schedule, prune lightly after the winter crop, and watch for new flowers; keep soil evenly moist.
- Summer: thin fruit if the crop is heavy, check for scale and stink bugs, and mulch to hold moisture.
- Fall: harvest the main crop, feed once more, and watch the forecast for early cold snaps.
- Winter: cover young trees when cold is forecast, and avoid pruning or fertilizing right before a freeze. Pick the late winter crop when it turns yellow.
Other warm-climate fruit to compare
Growing other subtropical fruit? Compare carambola with the sapodilla tree, lime trees and the cold-tolerant Blue Java banana. A Meyer lemon tree in a pot is another warm-climate fruit that adapts to containers.
Safety and legal note: People with kidney disease, reduced kidney function or on dialysis should avoid star fruit and juice made from it, and anyone unsure should ask a doctor. Keep fruit away from pets that have kidney problems. If you use fertilizer or pesticides, the label is the law. Rules on moving plants and fruit between regions, especially in quarantine areas such as parts of Florida, Hawaii and California, vary by state and country.
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Frequently asked questions
Is star fruit the same as carambola?
Yes. Carambola is the common name for Averrhoa carambola, the star fruit tree.
Yes. Carambola is the common name for Averrhoa carambola, the star fruit tree.
How fast does a star fruit tree grow?
Fairly fast in warm climates. Grafted trees can fruit about 10 to 14 months after planting.
Fairly fast in warm climates. Grafted trees can fruit about 10 to 14 months after planting.
Can you grow star fruit in a pot?
Yes. A grafted tree in a large container with well-drained potting mix can fruit and can be moved indoors in winter.
Yes. A grafted tree in a large container with well-drained potting mix can fruit and can be moved indoors in winter.
Who should not eat star fruit?
People with kidney disease or reduced kidney function should avoid star fruit, as advised by UF/IFAS. Ask a doctor if you are unsure.
People with kidney disease or reduced kidney function should avoid star fruit, as advised by UF/IFAS. Ask a doctor if you are unsure.
Do you eat star fruit skin?
Yes. The thin waxy skin is edible. Trim the brown edges of the ribs and remove any seeds.
Yes. The thin waxy skin is edible. Trim the brown edges of the ribs and remove any seeds.
How cold can a star fruit tree tolerate?
Young growth can be killed at about 30 to 32°F, and large branches and mature trees may die at 20 to 24°F, according to UF/IFAS.
Young growth can be killed at about 30 to 32°F, and large branches and mature trees may die at 20 to 24°F, according to UF/IFAS.
For other trees and berries to grow alongside this one, see the home fruit tree guide.
Reviewed October 2026. Sources: UF/IFAS St. Lucie County, Growing Star Fruit (Carambola) in Florida; UF/IFAS Gardening Solutions, Star Fruit; UF/IFAS Charlotte County, Wish Upon a Starfruit. This is general gardening information; ask a doctor about any health concerns.
