Magnolia is a genus of flowering plants with more than 1,000 cultivars. The southern magnolia (Magnolia grandiflora) is one of the more commonly grown varieties in the United States. Growing to 90 feet tall, the southern magnolia has large green leaves and striking white flowers. Magnolia trees are easy to grow and require full sun and acid soil. If you grow azaleas, you can fertilize them and a magnolia at the same time, with the same azalea fertilizer. Apply the fertilizer when the soil is dry, in early spring.
Rake the soil around the magnolia tree and bag up the debris.
Pour the fertilizer into a broadcast spreader, at the rate suggested on the package for the size of your tree.
Apply the fertilizer beginning at the outer two-thirds of the distance from the trunk to the dripline. Determine the radius of the widest part of the tree. Spread the fertilizer 50 percent of that measurement beyond the dripline.
Water the application area if no rain is expected.