I know that there are 2 schools of thought about pruning at planting time. I prefer the school of thought that advocates not pruning when planting or transplanting. The reasons I believe this is the best course are two-fold. First, removing foliage causes some stress to a plant. Add the pruning stress to the transplanting stress and you may cause the plant to decline and maybe die. The second reason is that roots need foliage to transfer food. The food necessary for the new roots comes from photosynthesis that occurs in the foliage.

Rather than pruning the top and sides of the plant, focus on watering and mulching your tree. Mulch protects the tree roots from becoming hot and dry. Another sidebar to the pruning process is fertilization at planting time. Avoid the temptation to load up with a hot fertilizer the first year. Use only a slow release dry fertilizer so the roots do not get stressed with an overload of nutrients.