How to Fertilize a Southern Magnolia

The Southern magnolia is a large evergreen tree. In summertime, its flowers often develop a white coloring. Certain adult Southern magnolias can reach 9 meters in height, while some can even grow larger. To help ensure these trees grow to maximum capability, it's important to fertilize Southern magnolias on a proper schedule, particularly in the first three years of a tree's existence.

8-8-8 or 10-10-10 fertilizer

Wait until the tree is established and exhibiting new growth before fertilizing. This will include blossoming flowers. At this point, growth can be aided via light, yet frequent, fertilizing applications during select growing seasons.

Tape off an area that is approximately three times the canopy spread. This will be the area in which fertilizing takes place.

Spread 1 lb. (or two cups) of 10-10-10 fertilizer or 8-8-8 fertilizer per 100 square feet. Consult a horticulturalist for more information regarding using 10-10-10 fertilizer vs. 8-8-8 fertilizer, both of which can commonly be found at garden and outdoor stores. Fertilization should take place in March, May, July and September.

Reduce fertilization to once or twice a year once a Southern magnolia reaches its fourth growing season.

Apply liquid fertilizers of your choosing over the course of a Southern magnolia's life, if desired, to supplement other fertilizers. This occurs mostly during the months in which your are not applying 8-8-8 or 10-10-10 fertilizer to a Southern magnolia. Follow the instructions on the bottle of liquid fertilizer for optimal results. This fertilizer can be found at most major outdoor retail outlets. Supplemental fertilizing is not necessary and may not make much difference in terms of how large a Southern magnolia grows.