There are two types of magnolias: evergreen or southern magnolias and deciduous magnolias. Both types produce fragrant flowers, have elegant arching branches and are considered premier landscape trees. The southern magnolia, however, does not lose its leaves in the fall. Evergreen magnolias will tolerate harder pruning than deciduous magnolias and can be trimmed, while young, into hedges. Neither type of magnolia likes hard pruning and care should be taken to remove as few large branches as possible. Adult magnolias should only be pruned to remove dead and diseased wood. Young magnolias can be more heavily pruned to enhance shape.
Wait to prune both evergreen and deciduous magnolias until they have finished blooming and the flowers are beginning to fade.
Remove dead, diseased and pest damaged branches. For branches over one inch in diameter, use a pruning saw rather than pruning shears.
Remove branches that are crossing or rubbing other branches and branches growing into the canopy. Remove the weakest branch or the branch that is growing into the canopy.
Remove water sprouts and suckers (growth emanating from the roots rather than branches or trunk).
Take a step back and evaluate the shape of the magnolia. If you like the shape, stop now. If the tree is lopsided, remove just enough to balance out the canopy.
Always cut branches off just outside the branch collar. Always use sharp pruning shears and saws. Disinfect your equipment between trees using diluted bleach.
Never remove more than one-third of the living tree in a growing season. If possible avoid removing large branches.