Magnolias are a fairly large group of plants, ranging from shrubs to tall trees. The 80 species of magnolias include both deciduous and evergreen plants. All are valued for their large, fragrant flowers and glossy foliage. When you plant your magnolia tree depends in large part on which type it is and whether your climate is tropical or temperate.
Evergreen magnolias should be planted in early spring. These include the large southern magnolia (Magnolia grandiflora) and the smaller sweetbay magnolia (M. virginiana), which is evergreen in the warmer parts of the South but can become deciduous in northern areas. The southern magnolia generally blooms in mid-to-late spring, depending on the cultivar. "Little Gem," for example, will bloom on and off throughout the summer. Some cultivars will bloom right away, while others may take years to bloom after planting. The sweetbay magnolia also blooms in May and June, with some cultivars that will bloom until September.
Deciduous magnolias, which lose their leaves when cooler weather arrives, can be planted in the fall or in early spring. Those that live in the far south should plant deciduous magnolias in the fall, when the weather is cooler. Northern gardeners should plant deciduous magnolia trees in the spring, when the soil warms up. Commonly cultivated deciduous magnolias include the saucer magnolia (M. x soulangeana), which is one of the earliest blooming magnolias (some cultivars will bloom in March) and the star magnolia (M. stellata). The star magnolia is also an early bloomer. Flowers appear in March, well before the leaves.
Magnolias thrive in rich organic soil, so amend the soil with 3 to 4 inches of leaf mould and work it into the soil before planting your tree. Choose a location that is in partial shade or full sun, if you are in a temperate climate. Magnolias like well-draining soil. Their somewhat delicate roots will rot if left sitting in standing water. Irrigate well after planting, then cover the area around the tree with 3 to 4 inches of mulch to help the soil retain moisture. Most magnolias will tolerate brief periods of drought.
Choose carefully when selecting a location for your magnolia tree. Magnolias in general have unusually shallow roots. For this reason, they should not be planted near walkways, where they can uproot concrete and asphalt. The roots are also quite fragile, which is why these trees should not be transplanted. Finally, if you are planting a southern magnolia, give it plenty of room to grow, as they can reach heights of over 75 feet.