A fruit tree will normally begin to bear fruit after it has become old enough to blossom freely. Nevertheless, the health of the tree and its environment, its fruiting habits and the cultural practices used can influence its ability to produce fruit. Adequate pollination is also essential to fruit yield. If just one of these conditions is unfavorable, yields may be reduced or the tree may not bear any fruit at all. The grower can exercise some control over most of the factors contributing to fruit production.

Bearing Age:

Nursery-grown fruit trees are usually from one to two years old. The length of time from planting to fruit bearing varies with the type of fruit. Trees growing at a moderate rate generally bear fruit sooner than those grown either too quickly or too slowly. Dwarf fruit trees usually begin to bear one to three years sooner than standard-size trees.

The age trees can be expected to bear fruit after planting:

Tree Health:

Healthy trees produce good quality fruit. Weak or diseased trees produce little or no fruit or fruit of poor quality. Preventing insect and disease damage is critical to tree health. It is often possible to control insect and disease problems without the use of pesticides or fungicides; see specific GreenShare Factsheets for more information and control recommendations. It is also possible to purchase varieties which are resistant to one or more of the common diseases.

Climate and Weather:

Most hardy fruit trees need a certain amount of cold winter weather to end their dormancy and to promote spring growth. When winters are too mild, spring growth is delayed, irregular and slow, the period of blooming is extended and the possibility of frost injury increased.

Extreme cold during winter dormancy, however, may kill the fruit buds. Winter weather rarely threatens apple, pear, plum and sour cherry varieties. Sweet cherry trees are relatively sensitive to cold until they become dormant. Peach trees are very vulnerable to cold weather; peach buds can be killed by midwinter temperatures of 10 degrees F below zero. The stone fruits--cherry, peach, plum and nectarine--can lose cold hardiness due to extended midwinter warm periods. Damage to the flower buds can be extensive, especially if the warm period is followed by a very cold period.

As the fruit buds grow and open, they become more susceptible to frost injury. The exposed buds can usually withstand temperatures near 24 degrees F, but blossoms of practically all fruit trees will be killed if the temperature drops below 24 degrees F. When a heavy frost is expected, covering the trees will sometimes prevent bud or blossom injury, provided temperatures do not fall too low and the cold weather is of short duration. Polyethylene sheets or plastic bags that reach to the ground are usually effective, but cheesecloth and even old bed sheets may be used.

During spring frosts, some commercial growers heat their orchards, but this method is impractical for most home gardeners. An alternative method is to sprinkle the trees with water. Start when the temperature falls to the low 30s. Keep the water running until all the ice is melted. Water must be dripping off the ice at all times or the plant will suffer from frost damage. After a severe frost, injured blossoms may appear normal, but if the pistils (center part of the blossoms) are killed, the tree will not bear fruit.

Pollination:

All fruit trees need to be pollinated. Without sufficient pollination, they may blossom abundantly but will not bear fruit. Some species of fruit trees have perfect flowers, where both the anthers, which contain pollen, and the pistils, which develop into fruit, are located in the same blossom. Trees that bear fruit as a result of pollination from their own anthers are considered self-fruitful. Self-fruitful tree fruits include quinces, sour cherries, apricots (except Perfection and Riland), peaches (except the J.H. Hale and several others) and European-type plums, such as the Stanley, Green Gage and Italian prune.

There are, however, many types of fruit with perfect flowers that cannot produce fruit from their own pollen. These require pollen from another variety and are called self-unfruitful. Self-unfruitful types include most apple, pear, sweet cherry and Japanese and American plum trees. To pollinate adequately, two or more varieties must be planted near each other.

Some species of fruit trees do not fit conveniently into either category. Some have pollen-producing male trees and fruit-producing female trees. To grow these successfully, it is necessary to plant at least one tree of each gender near each other. When selecting the varieties of the self-unfruitful tree fruits, verify that the flowering periods of the different varieties overlap. The following planting practices are recommended for the self-unfruitful plants.

Apple: Plant at least two varieties of apple trees near one another. Golden Delicious, a self-fruitful type, is one of the few exceptions to this rule. Poor pollen-producing types, such as Baldwin, Gravenstein, Stymen, Winesap and Rhode Island Greening, need to be planted with at least two other varieties to ensure adequate pollination of all.

Pear: Many varieties of pears are completely or partially self-unfruitful. For adequate pollination, plant at least two varieties together. Note: Bartlett and Seckel pears will not pollinate each other and Magness cannot be used as a pollinator.

Plum: Since most varieties of Japanese and American plums are self-unfruitful, plant two or more varieties together.

Sweet Cherry: Bing, Lambert and Napoleon (Royal Ann) cherry trees do not pollinate one another. Plant a pollinating variety, such as Black Tartarian, Republican, Van or Windsor, or a sour cherry, such as Montmorency, nearby.

Biennial Bearing:

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 are set during the previous summer, and 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. Thirty 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. Avoid placing fruit trees where they will be shaded by buildings or by other trees. Trees will grow more vigorously and bear better if they have adequate space to develop their root systems. Do not plant where roots of trees or large shrubs will compete for water and plant nutrients. Cultivate or mulch as necessary to reduce competition from weeds or grasses.

Apply adequate amounts of fertilizer to produce strong growth. Avoid excess fertilizer, which will produce weak, leggy growth and delay the setting of flower buds. Prune young apple trees to develop a strong framework with a central leader and horizontal branches. Excessive upright growth will delay fruit bearing and reduce the quantity of fruit produced.

Adapted from Edmond L. Marrotte, Department of Plant Science, University of Connecticut
and USDA Leaflet No. 172