Because thundercloud plum trees contain sap, the best time to prune them is in the late spring when the sap bleeds the least. Prune before the prime growing season to encourage the formation of new growth. Use pruning shears for small branches and a saw for larger ones. Keep pruning implements sharp to ensure clean cuts. Always prune as close to a bud as possible.
Prior to the growing season, remove branches that interfere with other growths or prevent the proper spread of sunlight and air circulation. Pruning after the growing season risks frost damage to new growths over winter. While the loss of sap is not damaging to the tree, many consider it unsightly, and most gardeners prefer to avoid it. The tree can repair open wounds from pruning by itself. Some gardeners prefer to paint over the opening to seal it more quickly, but experts agree that paint is not necessary. In addition to regular, yearly pruning, also remove damaged, diseased and dead branches as soon as possible because these pull energy from the rest of the tree and risk animal infestation and disease spread. Check trees for new damage after severe weather. Sterilize pruning implements frequently to avoid spreading diseases or pests throughout the tree or to other plants.