How to Prune a Magnolia Bush
Magnolias are either trees or bushes and are named for their familiar flowers. They bloom in early to late spring with pink, purple or white flowers from 3 to 12 in. wide. After the initial bloom of flowers, magnolias sprout green leaves, followed by reddish-brown seeds in early fall. Magnolia bushes do not require a lot of pruning to maintain its shape, but there are a few pruning techniques that will keep the plant healthy and properly-sized for your landscape.
Wait until the tree is finished blooming with flowers for the season before pruning. Magnolias are an early blooming plant, sprouting its flowers early in the spring. Pruning immediately after the season's bloom will ensure that you don't damage the next year's cycle.
Train into the proper shape during the first few years of the bush’s growth. To shape into a bush, keep pruning the branches back down while leaving the magnolia plant in the normal circular shape that it will naturally grow into.
Remove or cut away any dead, decaying or infested branches. If a branch fails to bloom during the preceding growing season, it is probably dead or dying and should be removed.
Trim branches that are rubbing together or rubbing across the trunk of the tree. Branches that rub against each other will damage the bark, which can expose the branches to infestation or disease.
Prune up to 1/3 of a magnolia bush each season all the way back to the ground to encourage new growth from the base of the plant. Try to remove even amounts of branches from all around the bush to keep the bush even and the branches properly spaced.
Prune a second time in mid-summer to cut back on the current season's growth. Cut down limbs that are noticeably longer than other branches and trim all branches back to a size that is appropriate to your yard or garden.
Magnolia bushes cannot withstand a lot of wind. They should be placed in a semi-sheltered area for protection or wired in especially windy locations.