tree planting is done during dormant winter months, most often after December 15th but before March 31st. You may need to do it a little earlier or a little later in warmer or colder climates. Your nursery can help you decide.
trees is a little different. Planting tree saplings has evolved into an all year operation because of the extra protection of a ball of earth around the roots. Any season is OK for planting balled or burlaped trees.
More Tree Planting FAQs