Magnolias grow best in full sun, at least half a day minimum. These trees tend to get leggy and lose their lower branches if they get too much shade. Flower production suffers also. To avoid frost damage in the spring, plant magnolia in a site where it's not exposed to early morning sun. This lets frozen flowers thaw slowly and reduces tissue damage and browning when there is a surprise early frost. Basically adaptable, magnolias can handle a wide range of soils. They are at home in acidic woodland settings as well as in more alkaline urban sites (pH 5.0 to 7.0). Exceedingly alkaline soils, however, will cause chlorosis, or yellowing of the leaves. As long as the soil has sufficient organic matter in it to assure good moisture retention and drainage, magnolias are happy.
Plant magnolias in sheltered areas if possible. Because their roots are slow to establish you might want to stake newly planted trees that are exposed to the elements for their first year. Drive 3 or 4 stakes into the soil equidistant from the tree out about 3 or 4 feet. Loop lengths of clothesline cord or other soft material, or ties from a commercial tree staking kit, around the tree stem about 2/3rds up its length and then tie each to a stake. Do not put strong tension on the lines, because the tree stem needs to room to flex somewhat so it will gain strength. Check the ties often to assure that there is no abrasion on the tree bark. Remove the supports after 9 months to a year. For more information see the file on Planting A Tree