When is the Best Time to Prune Magnolia Trees?

A Question Not Only of Timing, but Also of Desirability

Campbell's magnolia tree (Magnolia campbellii) in bloom.
Ellen Rooney/Photolibrary/Getty Images

"I have a lovely magnolia tree that I planted about eight years ago," wrote a reader of this Landscaping site. "Sometimes, my tree blooms twice a year. It is getting very wide and tall now. I would like to know when to prune it. Or maybe I should ask if and how I can trim it back into a more compact size. People have said that magnolias should not be pruned back; is this true?"

The response to this reader's email question follows:

When to Prune Magnolia Trees -- and How to Do It

Pruning really is not widely considered a must (or even desirable) for this popular flowering tree. For one thing, magnolia trees do not heal as well as most trees from pruning cuts (which can lead to the introduction of diseases), and, for another, you generally spoil the looks of a magnolia tree by pruning it. But if you still decide to prune, consider this advice:

  1. Do so just after flowering is done, not only so you can at least enjoy the current year’s blooms, but also because magnolia trees bloom on old wood (which means that pruning too late in the year puts you at risk for losing the buds for next year's flowers).
  2. Trim off only a small amount, perhaps to shape the plant to your liking.

Because magnolia trees heal relatively poorly after you prune them, making them susceptible to diseases, also keep the following in mind if you feel that you must prune:

  1. Make your cuts with pruners or loppers that have first been thoroughly disinfected (for example, with ethanol or isopropyl alcohol) and sharpened.
  2. Begin by cutting off dead branches and -- especially -- any limbs that you suspect are already infected by a disease (you want to make sure that the disease does not spread). Disinfect your cutting tool once again after this part of the job is done and before continuing to prune.
  1. When you start pruning the "good" branches, be sure to make clean cuts. Prune all of the way through the wood. Do not leave a branch hanging "by a thread" and then attempt to yank it off with your hand. In the process, you could end up ripping some bark off the trunk. 

Pruning After Damage From a Storm (Wind, Snow, Ice, Etc.)

Having advised, above, against pruning magnolia trees unnecessarily, an addendum is needed to conclude this article. For, sometimes, Mother Nature has a way of stepping in and forcing us to throw all of the "rules" out of the window. Consider the following scenario:

  1. During a severe wind storm (or snowstorm or ice storm), a huge pine bough falls on your 'Jane' magnolia tree.
  2. An accidental "pruning" results from the damage. That is, the tree's leader is broken, altering its shape and growth habit forever.
  3. Your 'Jane' magnolia takes on a shrub form thereafter.

After such damage from a winter storm, you may wish to change your approach in how you prune the magnolia. Accepting the fact that it will now be growing as a shrub (not a tree), maybe you will now want to prune it so as to give it the most pleasing shape that you can within the limits of its new plant form. The tree, or "upright" form (with no pruning) may have been the ideal, but it is advisable to adapt your expectations -- and pruning regimen -- to the new reality.

By pruning the damaged plant judiciously, at least you will be able to maintain it as a compact shrub that fits neatly into a designated nook or cranny in your landscape. In other words, depending on your own personal tastes, while the "wild look" may suit a magnolia just fine in tree form, a more manicured look may suit the plant better in shrub form.