Black cherry trees (Prunus serotina) are rarely grown in Hawaii, but will thrive in cooler, locations above 2,000 feet, where winter temperatures are dependably low for several months of the year, and summers are moist and cool. These trees generally fail in hot, lowland or coastal environments. This cherry, also called American black cherry, or rum cherry, is a tall, handsome tree, native to the eastern United States and the mountainous regions of northern Mexico. Black cherry trees may grow to heights of 100 feet at maturity, and produce small white flowers, which develop into drupes of delicious, deep purple to black cherries.
Purchase healthy grafted trees from a reputable nursery. Buy at least two trees for your fruit set, since, like many other cherries, black cherry trees do not self-pollinate. Buy your black cherry tree only when you are ready to plant it in the ground so that it won't become root-bound or otherwise stressed. Plant black cherry trees in Hawaii at the onset of the winter rainy season for best results.
Select a location to plant your black cherry trees with well-drained soil, where they will receive full sun. Dig planting holes at least twice as deep as the height of the pot in which the tree is growing and three times the pot's diameter. Add black cinder to the bottom of the hole and the backfill, if needed, to achieve good drainage. Add well-rotted organic compost to nutrient-poor soils. Plant your trees so that the crowns are exactly even with the new soil level. Water well at planting time and then irrigate regularly for the first year, or until established.
Drive three 6-foot-long wooden stakes at least 1 foot into the ground, in a triangular shape around the newly planted black cherry tree, just outside of the planting hole. Cut three pieces of rope at least twice the distance from the trunk to the stakes and thread each piece through a 1-foot length of bicycle tire inner tube. Attach the ropes firmly around the tree's trunk, leaving a few inches of slack on each side to allow for some movement. Remove the ties and stakes after the first year of growth. You may want to leave the ties for two years in areas prone to strong winds.
Fertilize black cherry trees lightly with a balanced fertilizer, or apply composted manure or well-rotted compost annually in late winter for faster growth and greater yields. Black cherry trees are adapted to poor, acidic soils and do not require heavy feedings.
Prune away dead wood and any remove any crossing branches from young black cherry trees. It is especially important to shape black cherry trees while young, because weak-wooded crossing branches are prone to breakage, and may seriously damage mature trees. Prune away live wood in late summer, after fruiting. Remove weeds under the canopy regularly.