The American Plum grows wild throughout most parts of the United States. Without trimming or pruning, it grows thick and tall. The roots spread, easily taking over an area. The trees are thorny, so gloves are recommended when caring for wild plum trees. Trim wild plum trees in June to prevent silver leaf disease; plum trees pruned during the winter are susceptible to infection.
Remove suckers that grow up from the roots whenever they occur. Wild plum trees have shallow roots which sprout easily. Unless suckers are removed regularly, the tree will spread into an undesirable thicket.
Trim wild plum trees in June to establish a pleasing shape and control growth to an acceptable size. Make cuts clean with pruning shears, or use a small hand saw for larger wood. Try not to crush or split the wood. Make all cuts immediately above a healthy bud that faces outward.
Prune branches to increase production. Remove new growth that does not have blooms or fruit. Trim leading shoots, removing approximately a third of the growth. Trim other shoots as needed to establish a good shape.
Remove branches in the center of the tree to open up the tree and let in light. Trim away branches that cross or rub against another branch. Remove all dead and diseased wood.
Seal large cuts with sealing compound to protect the cuts from disease.
Remove all trimmings and debris from the area, and burn it to prevent the spread of disease.