Tulip magnolia (Magnolia x soulangeana) is also known as saucer magnolia. Both names come from its large, tulip-like flowers that open to wide saucer shapes. This deciduous hybrid magnolia, hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9, blooms in early spring. It produces white flowers heavily flushed with purple. As with many flowering shrubs and trees, pruning is best done right after flowering.
Tulip magnolias grow from 20 to 25 feet tall, with an equal spread. The plants can be grown as multistemmed shrubs, but are often pruned into tree form by selecting a strong central trunk on a young specimen and systematically pruning away all other stems. After the first flush of bloom ends, a few more flowers may appear on the plant during the summer. Pruning may reduce the occurrence of these "bonus" flowers. Tulip magnolias occasionally develop cone-shaped red fruits, but they are rare. The glossy, oval-shaped green leaves turn yellow in the fall.
When you prune in late spring, aim to remove dead branches and encourage the magnolia's natural, rounded crown. If the tree has reached its mature height and needs extensive pruning, it's best to consult an arborist. Use clean, sharp tools, including a pole saw for higher branches. Trim individual branches close to lateral buds to encourage new growth. If you must remove entire branches, trim them close to the tree's trunk. Large branches have a swollen ridge and collar adjacent to the trunk. Leave the ridge and collar in place when pruning.
The exception to the late spring pruning rule comes up after storms that cause damage to the tulip magnolia -- especially specimens grown in tree form. After severe wind or ice storms, check the tree thoroughly for damaged branches or dangerous "hangers." Prune them as soon as it's safe to do so, no matter what time of year, because damaged branches are unlikely to produce flowers in the future.
All trees, including purple tulip magnolias, need some pruning from time to time. However, pruning a tree because it has been planted in a space too small to accommodate its dimensions is difficult. If this is the case and the tree is still young, consider transplanting it to a better location. This is best done in very early spring or early fall. If the tree is fully mature, the only alternatives are careful pruning every year or, if the magnolia is not flourishing because it is too crowded, removal of the tree.