GARDEN COLUMN FOR THE SALISBURY POST
Darrell Blackwelder
November 1, 2002

          Homeowners are often frustrated when fruit trees, nut trees and other small fruit plants fail to bear fruit, including ornamental plants. Homeowners have the ability to reduce some of the factors that reduce flowering and limit or impede yields. Now that the season is over for many fruit bearing plants, homeowners may be able to correct problems associated with non-bearing or poorly bearing fruit trees or shrubs. The long term drought may be a key factor with poor fruiting; however, there are other factors that should be considered.
        Too much shade. Fruit trees and small fruit need be located in full sun. Reduced light will reduces the amount of flowering hormones within the plant, therefore less flowers. Often trees or plants do poorly in shady areas. Peach and apple trees become weak and disease prone in shady areas. Prune trees back to allowing ample sunlight to the trees or relocate trees to a sunny location.
   Plants are not mature. Peach and apple trees require about four year's to produce an appreciable crop. Fruit may occur earlier, but will weaken growth of the tree. Thin fruit from newly set trees to allow good fruit set. Pecan trees may take up to 12 years of growth for an appreciable crop. Grapes, blackberries and some strawberry varieties may take from two to three seasons to produce a crop for harvest. Be patient. Some dwarf fruit tree cultivars produce fruit at an early age. Home gardeners should consider these types of trees before planting or when replacing older trees.
Plants are located in a frost pocket. Fruit trees and small fruit located in low lying areas are subject to late spring frosts. Peaches and apple trees should be located on upland areas that receive wind movement from prevailing winds. Wind movement stirs pockets of warm and cold air, often reducing chance of late frosts. Never locate a spring flowering fruit crop in a low area or valley.
        Improper pruning practices. Plums, peaches, nectarines and other stone fruits should be pruned as late as possible, even when the buds are showing color. Pruning stimulates growth; therefore early pruning forces trees to bud early, especially in unseasonably warm winters. Early pruning forces early blooms. Prune as late as possible; from late February to mid-March. Early spring pruning does not damage fruit trees.
Poor soil. Soils low in phosphorus will not produce adequate blooms. Highly eroded fields or cleared topsoil from a construction site reduces the phosphorus index in the soil. Low pH will also impede growth and reduce blooms. Take a soil sample before planting trees, especially on a site where the topsoil has been removed. Proper amounts of lime and phosphorous need to be tilled into the soil before planting.
       Alternate or biennial bearing. Apple trees and pecan trees sometimes have this problem when bumper crops are produced. Food reserves are drained from overbearing trees reducing food for the next seasons' crop. The next season the tree bears a small crop overproducing food for an upcoming bumper crop creating a cycle. The solution is to thin fruit laden trees to reduce the drain on next season's food reserves. Few homeowners follow this advice.
Poor pollination. Some tree fruit varieties do not produce adequate pollen or enough pollen to produce fruit. "Red Delicious" apples require a pollinator, usually a "Golden Delicious" apple, to complete the pollination process. Some muscadine grapes only produce male or female flowers. Grapes with a complete flower must be planted near to provide pollen to complete the process. Some pecan trees produce pollen, but produce it too early. Some pecan species flower produces pollen six weeks before the female flower is receptive. Different pecan varieties planted nearby insures proper pollination. Honey bees are important pollinators. Cloudy, cold, weather often limits bee flight therefore reducing fruit set. Protect not only honey bees but all pollinating insects by reading instructions of all pesticides before application. Sevin is deadly to bees and other pollinating insects.
        Drought. Prolonged droughts seem to have little affect on some fruit set, but can be devastating on others. Reduced humidity and moisture produces fruit with less disease, but can also reduce quality in terms of size and in some instances quantity of fruit. Pecan trees suffer from lack of moisture.

Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. For archived garden columns or other information, visit the Rowan County Master Gardener web site at www.rowanmastergardener.com or e mail Darrell_blackwelder@ncsu.edu or phone at 704-633-0571.