Our site is reader supported, this means we may earn a small commission from Amazon and other affiliates when you buy through links on our site.
Magnolia Stellata is a deciduous magnolia tree. As such, it only needs some light pruning. Over pruning of magnolias leads to health issues for them as well as issues with flowering.
Magnolia stellata is one of the varieties that can be grown against a wall or fence and shaped, in this case, you can lightly trim them after flowering in spring.
If you have one that is too large and needs pruning more significantly, then I recommend renovation pruning over 2 to 3 years removing up to a third and this is best done in late summer. Basically, the lighter you can prune the better to retain the flowers for the following season.
You can remove diseased or dead shoots when you notice them. If you have long vertical shoots, these are known as water shoots and should be pruned right back to the main branch.
We have a detailed article about pruning magnolia trees in general. Please read When and how to prune a magnolia tree? and follow the directions for deciduous trees.