White Mulberry trees should be pruned during the dormant season in winter or early spring. Here are some tips for pruning: 1. Remove any dead or damaged branches. 2. Remove any crossing branches that are rubbing against each other. 3. Remove any branches that are growing towards the center of the tree. 4. Thin out the branches, leaving about 6 inches of space between each branch. 5. Cut back any long growth to encourage branching and a fuller shape. 6. Do not remove more than 1/3 of the tree's overall foliage in one year. 7. Use clean, sharp pruning shears and make clean, smooth cuts. It's important to note that White Mulberry trees can have invasive growth habits, so regular pruning is necessary to keep the tree under control.