It really depends on a number of factors and your personal preference. Is your area subjected to freezes every winter? That is a main consideration. Younger trees are less hardy in those conditions than older trees. Although you can plant them, then dig them up and bare root them over the winter, it is more work than moving the pots. Certainly they grow better when not restricted to pots.

Mine are all kept in pots at the moment. Some are plunged, others are not. I planned to put some into the ground this year, but I haven't yet due to lack of time and the number of rain days we've had this summer.

astrl