What cultivar do you have? Young evergreen magnolias are best trimmed in mid to late spring only when needed. Deciduous magnolias should be pruned between midsummer and early fall.

Although pruning magnolia trees is not necessary, young trees can be shaped as they grow. Trimming a magnolia tree when it is young will also improve the health of the tree and encourage more blooms.

Mature magnolia trees do not recover from pruning and can sustain fatal wounds. Therefore, magnolia tree pruning on older specimens should only be done as a last resort when necessary.

Sometimes you have to and we did it in the dormant season

its a bit young to flower maybe.....whats the variety, ours is a Stellata cross....

Not sure of the variety as it was given as an unlabeled present and it has not flowered yet.

OK, If it kept its leaves all winter, prune it now. If it grew new leaves in the spring, wait until September.