|For best size control and fruit on Apple, Apricot, Mulberry, Nectarine, Peach, Plum, and Pomegranate Trees, prune during the summer months.
For height control, cut new growth back to the desired size in June. The remaining stubs will re-sprout quickly. In early September, cut back again, just below the newest sprouts. This method is called Double-Heading. It is OK to prune at any time during the summer to keep the tree at its desired size; double-heading is simply less time consuming.
Most of us were originally taught to prune in winter. More recently, authorities told us to prune in the fall. The latest research has proven that summer pruning is most effective. This is because these fruit trees do not grow during the fall; therefore, any foliage remaining after summer pruning will gather energy all fall for the next year's crop. Heavy winter or fall pruning eliminates wood that has already stored ample energy, leaving underlying wood with less potential for fruiting.
It was also thought that trees should be pruned when dormant because less sap leaks out. Now we understand that this leaking is actually beneficial to the trees as a natural defense mechanism.