Thanks for writing. Was your tree exposed to a lot of wind on the trip home from the nursery? If it was sticking out of a car window or the back of a truck, it could be suffering wind damage. If this is the case, then there's not much you can do but be patient and wait for it to bounce back.
Does the container have a drainage hole? If not, its roots could be starting to drown. Make sure there's a way for excess water to escape the plastic container.
---Justin, Senior Garden Editor, BHG.com"