Because of blooming periods that vary widely from variety to variety and don't always coincide, plum trees often do not set good crops of fruit. Only a few types are self-pollinating, so planting different plum varieties together does help. Since honeybees and some other insects pollinate plums by transferring pollen from tree to tree, orchard hives increase the chances of a good yield. Success isn't certain because bees often prefer other types of forage. Mechanically applying commercially harvested pollen requires equipment most small-scale growers don't own.
Choose plum varieties that bloom at overlapping times. Nurseries and Extension Services provide charts of compatible plum cultivars. Since bees prefer traveling along rows, plant pollinator plums in each row of fruiting plums and not in rows of pollinators only.
Cut back competing plants while plums bloom. Eliminate other flowering plants in the orchard by mowing during the blossoming phase to focus the foraging efforts of the local honeybees on the plum trees.
Place beehives in the orchard during the bloom so that the bees encounter the plum blossoms first. Bees ranging beyond the trees will still work the plum tree flowers in passing.
Set pollen applicator troughs at the entrances of bee hives. Add one teaspoon of commercially produced plum pollen to the trough each day. Bees leaving the hive take pollen with them, increasing the pollination rate in the orchard.
Use scissors to square the end of a No. 4 artist's paint brush to 1/4 inch bristle length. Dip the brush in a small container of plum pollen and daub the center of a plum flower to hand pollinate small plantings. Fertilize one flower in every six to avoid unusually heavy fruit set.