Plant a pollinating variety, such as Black Tartarian, Republican, Van or Windsor, or a sour cherry, such as Montmorency, nearby. Occasionally certain fruit trees, such as apples, bear heavily one year and sparsely the next. This is called biennial bearing. The buds of most hardy fruit trees have been set during the previous summer. Therefore, an especially heavy crop one year may prevent adequate bud formation for the following year.
Biennial bearing is difficult to alter or correct.
However, it is possible to induce a return to normal yearly fruit production by early and heavy thinning during the year in which the trees are producing their large yield. About 30 to 40 healthy leaves are needed to produce good quality fruit. Within 30 days after bloom, thin to leave only four to seven fruit per yard along the branches. Cultural Practices Fruit trees need full sunlight for best production. Inadequate sunlight delays the beginning of flowering and may reduce the amount and size of fruit.