Certified GKH Gardening Expert
Magnolias will show transplant shock after planting and even into the next growing season.
Many of the older leaves will turn brown, yellow or drop from the tree.
As long as some of the terminal leaves remain and you are getting new leaf growth, the tree should survive and resume it's normal growth the following year.
Make sure you provide additional water during the Spring through the Fall.
Adding 2 to 3" of hardwood mulch will help with moisture retention.