How to Boost a Carambola (Star Fruit) Tree From a Graft
The carambola tree (Averrhoa carambola L.), most commonly known as the star fruit tree, which is a medium-growing evergreen that is capable of reaching 25 feet wide by 33 feet tall. Hardy into U.S. Department of Agriculture plant hardiness zones 9 through 11, the carambola tree creates ovate, star-shaped edible fruit which has translucent yellowish skin and grows up to 6 inches long. The carambola tree is principally created from grafted rootstock. Grafting is performed when a professional takes a youthful division from a mature tree and adds it into the rootstock of another plant. Grafted carambola trees can be purchased locally at select garden center retailers and could be grown with great results, if special care is given.
Dig a hole with a scoop twice as wide but no deeper than the rootball of the carambola tree. Set the tree in the hole and backfill around the rootball with a mixture of 50 percent indigenous dirt and 50 percent organic compost. Pick a place that is sheltered from the end, receives full sun exposure and also has well-draining dirt.
Water that the carambola tree from spring through fall using a watering hose that is put on a slow drip. Water to a depth of at least 12 inches for up to three years following transplant when mud isn’t adequate. Permit the soil to dry out between watering, as carambola trees don’t like constantly wet roots.
Apply a 4- to 6-inch layer of organic mulch around the base of this carambola tree, 8 inches from the trunk into the outer edge of the canopy. Organic mulch can help to retain moisture, reduce weeds and prevent mechanical damage to the trunk from mowing.
Fertilize the carambola tree once per month, spring through fall by sprinkling 1/4 pounds of 6-2-6-3 granular fertilizer containing nitrogen, phosphorus, potassium and magnesium round the base of this tree, from the trunk into the outer edge of the canopy.
Eliminate the tips of new shoots on the opposite branches with pruning shears by cutting 1/4-inch above the leaf node at a 45-degree angle, then one or two years following transplant to promote branching. Do not cut on the central leader. Remove any dead or broken branches with pruning shears by cutting the branch flush with the trunk or lateral branch.