Planting a Tree by Sir George Clausen
Autumn is the best time of year to plant trees. Not only is the heat of summer over and the water needs of trees is lessened, but the soil is still warm enough to encourage root growth. And, this is great time to take advantage of end of season sales at nurseries. Just be sure to plant early enough that plants get off to a good start before the ground freezes.
It takes less than a minute in bright sunlight for small feeder roots to die, so protect the roots before planting. Without these, the plant must struggle to absorb moisture; transplant shock will be greater and survival lower. Make the planting hole at least a foot greater in diameter and six inches deeper than the plant's rootball. If your soil is heavy, loosen it on the inside of the hole.
In general, plant at the same depth as the plant grew in the nursery. Set the graft union on fruit trees about two inches above the soil line and the union on grafted roses about two inches below the soil line.
Use plenty of water in the planting hole, but no fertilizer. And finally, put a thick organic mulch around the plant to protect it from winter damage. Be sure to allow space between the trunk and the mulch to avoid rodents' nesting next to the trunk.
If you form a basin around the base of the tree to hold irrigation water during establishment, be sure to break a hole in one side of the mound before winter. This allows puddle water to drain away from the trunk, preventing it from freezing and damaging the trunk and root system.