The magnolia tree holds a sentimental place in the heart of America as a tree that is strongly associated with the Old South. Most magnolia tree varieties are tender and susceptible to freezing weather or frost damage. Several new cold-hardy cultivars have been developed that can flourish without protection even in the northern-most regions of the United States. The magnolica grandiflora is easily susceptible to even a minor frost and its leaves will sustain damage.
Plant the magnolia tree in a southern, full-sun location. Place the plant beside a house, building or solid fence to afford it winter protection and keep chilling winds from taking their toll on the tree's delicate foliage.
Apply 4 inches of mulch around the base of the tree and outward to the tree's drip line.
Cover the magnolia tree with blankets the night before a heavy frost is predicted. Remove the blankets the next morning after the sun rises and the surrounding environment warms.
Irrigate the magnolia tree and the surrounding grounds with water, using a garden sprinkler, during a heavy frost to insulate from freezing. Begin irrigating the tree when the temperature dips to 34 degrees F. Continue watering the tree through the night to protect it from the frost. Keep the tree's foliage continuously moist through the night. Discontinue watering when the sun rises and the outside temperature begins to warm up past 34 degrees F.