Deciduous trees can be planted in spring once all frost is out of the ground or during the fall time from leaf-fall until freeze-up.
Conifers can be planted early in the spring until four weeks or so after deciduous trees have opened their leaves, or in the fall from around the first week of August to the end of October.
If you’re unsure of what type of tree you have, early spring right after the ground thaws is a pretty reliable time for planting. Trees have a risk of not taking root in the fall, making tree-planting riskier. If you do opt for fall for any reason, we recommend looking for trees with roots wrapped in a burlap bag instead of soil-free roots for fall planting, as these bare roots may not survive winter conditions.