Carambola (Averrhoa carambola L.) growing for the

home landscape

Jonathan H. Crane, Tropical

Fruit Crop Specialist

University of Florida, IFAS

Tropical Research and Education Center Homestead, Florida

2002

AcknowledgementsMaria Lilia Caldeira, TechnicianLaurel C. Crane, TechnicianRobert J. Knight, Jr., Geneticist/Plant BreederRoberto Núñez-Elisea, Plant PhysiologistIan Maguire, Media Artist*Jorge E. Peña, Prof., EntomologistRandy C. Ploetz, Prof., Plant Pathologist*Osvany Rodriguez, Field Technician

*, photographs copyrighted by I. Magure, R. Ploetz and UF.

Background

Common names include star fruit, bilimbi, and five-finger.

Member of the Oxalidaceae.

Indigenous to southeast Asia.

Distributed throughout many tropical and warm subtropical areas of the world.

Grown commercially in Taiwan, Malaysia, Guyana, India, Philippines, Australia, Israel, and the US (Florida, Hawaii, Puerto Rico).

Description Carambola trees are

small to medium height (20-30 ft) and width (20-25 ft).

Generally, evergreen, although looses some or all leaves during winter/early spring in Florida.

Upright to spreading growth habit. The canopy may be globose to oblong in shape.

Description

Carambola have compound leaves with 6-12 leaflets per leaf.

Carambola flowers are borne on panicles on twigs, small diameter branches, and occasionally on larger wood.

Flowers are perfect, small, pink to lavender in color, and have 5 petals and sepals.

Description

The fruit is a 4 to 5-celled berry with 0 to 12 edible seeds.

Fruit range in size from 2 to 6 inches with 4 to 8 ribs; cut in cross section the fruit has a star shape.

The fruit skin is edible, smooth, and waxy.

The fruit flesh is juicy, light to dark yellow in color, crisp, and without fiber. Good cultivars have an agreeable subacid to sweet flavor.

‘Sri Kembangan’

Description

In Florida, carambola trees have two major blooming periods (April-May, September-October) and fruiting seasons (July-September and December-February).

Fruit may be picked when they turn light to medium-yellow to dark yellow in color. Fruit become sweeter as color becomes darker, however, best flavor is at the medium-yellow stage of development.

‘Arkin’

Adaptability Carambola trees are

best adapted to hot, humid, tropical climates but do well in warm subtropical areas (like Florida).

Trees grow rapidly and best fruit quality is produced in locations protected from strong winds.

Trees are well adapted to many well-drained soil types (e.g., sands, crushed limestone, muck). Moderately susceptible to flooding. Moderately acid to neutral soil pH is best.

Adaptability Carambola trees grow

and fruit best at temperatures above 65oF and below 110oF. At cool and excessively hot temperatures growth and production decrease.

Cold tolerance - Air temperatures of 30o to 32oF may kill young leaves; young trees, twigs, and mature leaves may be killed at 27o to 29oF.

Small branches may be damaged at 25o to 29oF and large branches and mature trees may be killed at temperatures of 20o to 24oF.

Carambola propagation

Commonly carambola are grafted (veneer, cleft, whip) or budded (chip) onto seedling rootstock.

Favored seedling rootstock comes from open pollinated ‘Golden Star’ and M-18960 fruit.

Air-layering (marcottage) and tissue culture have not proved successful at this time due to poor root development. ‘Golden Star’

M-18960

Planting a carambola tree

The best time to plant a carambola tree is during the rainy season (May-September).

Select a sunny, wind protected site with well-drained soil.

Plant only healthy, vigorously growing trees.

Plant 25 or more feet from adjacent trees and structures.

After planting, water the tree in, tamping the soil around the base of the tree lightly.

Apply a very small amount of fertilizer when the tree begins to grow.

Carambola pollination

All the flowers of a given carambola cultivar have either long or short styles.

Some carambola cultivars may require cross pollination for good fruit set and yields. However, many set sufficient fruit for home use.

The cultivars ‘Arkin’, ‘Kary’, and ‘Fwang Tung’ are known to set sufficient fruit without cross pollination.

Fertilizer practices for carambola trees Young trees should receive ¼

to ½ pound of a mixed fertilizer containing nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) every 30 to 60 days.

During spring and summer, a minor element mix (manganese, zinc, boron, etc.) may be applied 4 to 5 times per year to neutral to low pH, sandy soils but, should be applied foliarly if trees are growing in high pH and/or calcareous soils.

Iron sulfate may be applied 4 to 8 times per year to neutral to low pH sandy soils. Chelated iron materials should be used for trees growing in high pH, alkaline, and/or calcareous soils. Mix the chelated iron with water and drench into the soil around the base of the tree.

Iron deficiency

Fertilizer practices for carambola trees

Mature trees should receive 1 to 3 pounds of a mixed fertilizer containing nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) every 2 to 4 months.

Like young trees, minor element foliar applications and soil drenches of chelated iron materials should be applied 4 to 5 times to mature trees during the warm season (March-October).

Watering carambola trees Newly planted

trees should be watered every days for the first 3 to 5 days.

Established trees should be watered every 3 to 4 days during dry periods throughout the year.

Symptoms of trees under drought stress include leaf wilting, yellowing and drop and reduced fruit set and size, and yields.

Pruning and tree size control The best time to prune

trees is during the growing season (March-September).

By selectively removing limbs trees can be easily kept at 8 to 15 ft high and 15 to 20 ft in diameter.

Tipping back long thin shoots 12 to 18 inches may induce flowering and off-season fruit production on remaining portions of the shoot.

Selected characteristics of recommendedcarambola cultivars

Cultivar Origin Flavor Comments

Arkin Florida Sweet Fruit good; very productive

Fwang Tung Thailand Sweet Fruit excellent, yellowish-white fruit

Kary Hawaii Sweet Fruit very good; small tree

B-10 Malaysia Very sweet

Fruit very good; may need cross pollination for good fruit production

Sri Kembangan Malaysia Sweet Fruit very good; fruit large

Kajang Hawaii Sweet Fruit good; medium to large fruit

Lara Florida Sweet Fruit good; possible commercial potential

• Origin: Florida• Medium size (7.6-12.7 cm; 3-5

inches long) and broad ribs

• Yellow to orange color

• Sweet (4-8oBrix) with good flavor

• Recommended for commercial planting.

‘Arkin’ carambola

6 inches

‘B-10’ carambola

• Origin: Malaysia• Medium size (7.6-12.7 cm; 3-5 inches

long) and broad ribs• Yellow to orange color• Sweet (8-11oBrix) with

good flavor• Recommended for

commercial planting. Plant with other cultivars for cross pollination.

6 inches

‘Fwang Tung’ carambola

• Origin: Thailand• Medium to large size (7.6-12.7+ cm; 3-5+ inches

long) and thin, wavy ribs• White yellow to light

yellow color• Sweet (6-10oBrix) with

good flavor• Generally recommended

as a dooryard fruit tree although may have some “specialty” market potential.

6 inches

‘Kary’ carambola

• Origin: Hawaii

• Medium to large size

(7.6-12.7 cm; 3-5+ inches long) and broad ribs

• Yellow to orange color

• Sweet (7-12oBrix) with good flavor

• Recommended for commercial planting; may have potential as a pre-sliced product.

6 inches

‘Kajang’ carambola

• Origin: Hawaii• Medium to large size (7.6-12.7 cm; 3-5+ inches

long) and broad, sometimes wavy ribs

• Light yellow to yellow color

• Sweet (6-10oBrix) with good flavor

• Generally, recommended as a dooryard fruit tree, however, may have some potential as a “specialty” carambola.

6 inches

‘Sri Kembangan’ carambola

• Origin: Malaysia• Medium to large size (7.6-12.7 cm; 3-5+ inches

long) and broad ribs• Light yellow to orange

color (mottling)• Sweet (7-11oBrix) with

fair to good flavor• Generally, recommended

as a dooryard fruit tree, however, may have some potential as a “specialty” carambola.

6 inches

‘Lara’ carambola

• Origin: Florida• Medium size (7.6-12.7 cm; 3-5

inches long) and broad ribs

• Light yellow to orange color

• Sweet (7-10oBrix) with good flavor

• Possible commercial potential, recommended as a dooryard fruit tree.

6 inches

‘Erlin’ carambola

• Origin: Taiwan

• Medium size

(3-5 inches long) and broad ribs

• Pale yellow to yellow color

• Sweet (4-8oBrix) with fair to poor flavor (insipid)

• Not recommended as a dooryard fruit tree.

‘Golden Star’ carambola

• Origin: Florida• Medium size (3-5 inches long) and

broad ribs• Yellow to orange

color• Tart (sour) (4-6oBrix

with high acid). Good flavor when very ripe.

• Not recommended as a dooryard fruit tree.

‘Miss’ carambola

• Origin: Taiwan

• Small to medium size

(<3-5 inches long) and broad ribs

• Pale white to light green/yellow color

• Sweet (6-10oBrix) with fair to poor flavor (insipid)

• Not recommended as a dooryard fruit tree.

‘Pasi’ carambola

• Origin: Taiwan

• Small to medium size

(<3-5 inches long) and broad ribs

• Pale white to light green/yellow color

• Sweet (6-10oBrix) with fair to poor flavor (insipid)

• Not recommended as a dooryard fruit tree.

‘Cheng Chui’ carambola

• Origin: Taiwan• Medium to large size (3-5+ inches long) and

thin, wavy ribs• Pale yellow to yellow

color• Sweet (3-8oBrix) with

fair flavor (insipid)• Not recommended as a

dooryard fruit tree.

‘Waiwei’ carambola

• Origin: Taiwan

• Medium to large size

(3-5+ inches long) and broad and wavy ribs

• Light green/yellow color

• Sweet (7-10oBrix) with fair to poor flavor (insipid)

• Not recommended as a dooryard fruit tree.

‘Wubentou’ carambola

• Origin: Taiwan

• Small to medium size

(<3-5 inches long) and thin wavy ribs

• Pale white to light green/yellow color

• Sweet (4-8oBrix) with fair to poor flavor (insipid)

• Not recommended as a dooryard fruit tree.

Diseases of carambolaLeaf spots are caused

by a number of fungi (Cercospora averrhoa, Corynespora cassiicola, Phomopsis sp., Gloesporium sp., and Phyllosticta sp.).

However, these are usually not a problem. They are more prevalent during the winter as trees begin to drop leaves. No control measures are necessary.

Diseases of carambola

Pythium root rot is caused by Pythium splendens. Symptoms include loss of tree vigor, leaf drop, twig dieback and reduced fruit yields. Healthy, vigorously growing trees are less affected. For control measures contact your local county agricultural extension agent.

Diseases of carambola

A superficial blackish discoloration on the fruit is caused by Gloeodes pomigena and is called sooty blotch.

No control is necessary as the sooty discoloration is harmless and can be washed off fruit before consumption.

Insect pests of carambola

A number of scale insects (Plumose and Philephedra) attack leaves and twigs causing defoliation and stem dieback. This may be controlled by judicious use of horticultural oil sprays. Caution: oil can cause defoliation if high rates are used or trees are drought stressed.

Mealy bugs and fruit blotch miners are occasional pests and usually do not warrant control.

Mealybug

Insect pests of carambola

Stink bugs (Nezara sp.) and squash bugs (Acanthocephala sp.) cause pinhole-sized marking on the fruit surface and dry areas of the fruit flesh under the puncture wounds.

These insects are only occasional pests and usually do not usually warrant control.

Insect pests of carambola

• Thrip damage.

Grasshopper damage

Animal damage

Birds, opossums, and raccoons may feed on the fruit. Their damage can be identified by the V-shaped marks left on the ribs of the fruit.

Control is usually not warranted.

Immature to horticulturally mature to ripe fruit

Harvest fruit when mature or ripe

Carambola storage and uses

Ripe carambola can be stored in polyethylene bags in the refrigerator (41o-50oF) for up to 21 days.

Carambola may be enjoyed as a cool, crisp, and juicy fresh fruit, cut up in fruit salads, used a garnish for meat dishes, and juiced, pickled, wine, marmalades, and dried.

Carambola fruit nutrient content –value per 3.5 oz (100 grams) of fruit

• Water, 91%• Calories, 33 kcal• Protein, 0.54 g• Total lipid (fat), 0.35 g• Vit. C, 21.2 mg• Folate, 12.0 mcg• Vit. A, 493 IU

Source, USDA

• Calcium, 4 mg• Magnesium, 9 mg• Phosphorus, 16 mg• Potassium, 163 mg• Sodium, 2 mg

For more information

• UF-IFAS publications web site: http://edis.ifas.ufl.edu

• UF-TREC FruitScapes web site: http://fruitscapes.ifas.ufl.edu or www.fruitscapes.info

• UF-TREC: http://trec.ifas.ufl.edu• Fla. State Hort. Soc.: www.fshs.org

Credits

• Author – Dr. Jonathan H. Crane, Tropical Fruit Crops Specialist

• Photographs – copyrighted– Ian Maguire– Jonathan H. Crane

• This presentation is copyrighted, 2005 University of Florida, Institute of Food and Agricultural Sciences