Plant a new tree successfully in the early spring or fall for best results, as suggested by University of Missouri Extension. Trees cannot be planted in the winter in many locations because of frozen ground. Summer proves difficult for tree planting as well, with high temperatures that stress the newly planted tree.
You should plant bare root trees in the winter or early summer when they are first available at the nursery, according to University of Missouri Extension. Trees experience less stress when planted during their dormant season at this time of year as well.
Plant trees in the fall if they are burlap-wrapped or grown in containers, as suggested by the University of Nebraska. These trees have a strong root system already in place and do not require extensive time to establish roots before cold weather sets in. Conifers do best when planted early in the fall season, but other trees can be planted past September.
Trees that are not planted soon after being prepared at the nursery suffer from extreme stress and are more likely to have trouble growing, according to the University of Minnesota.
The best time to plant a new tree also varies widely depending on your location, but temperatures provide an accurate way to identify the best planting time. Most trees can continue growing, developing roots and adjusting to planting even when soil temperatures cool to 45 degrees F, according to the University of Nebraska. The exception is conifers which should be planted in soil temperatures of 60 to 70 degrees F.