Gary L. Wade, Extension Horticulturist
Southern Magnolia, Magnolia grandiflora, is an aristocrat of trees. It grows well throughout Georgia, is widely adaptable to a variety of soils, and has few pest problems. With glossy evergreen foliage and large white fragrant blossoms, it truly is one of the most handsome and durable native trees for our Southern landscapes.
Most cultivars of Southern Magnolia are seedling selections that have been vegetatively propagated. Some nurseries also sell seedling trees. However, seed propagation results in a wide variety of tree shapes, leaf sizes and coloration of the leaves. In addition, seedling trees may take 10 years to flower.
Today, there are several superior cultivars of Southern Magnolia on the market. Many new cultivars flower at an earlier age and have a tighter, denser canopy or smaller growth habit than the seedling forms. Another popular characteristic is a rusty-bronze appearance of the underside of the leaves. Table 1 lists several new cultivars on the market.
Southern magnolia is most frequently grown as a single specimen tree in the landscape. Its coarse-textured leaves provide an excellent background for shrubs, particularly needle evergreens. Since the tree sheds old leaves each spring and seed pods in late summer, it is best to plant it in an ornamental bed instead of an open lawn area.
A row of Southern magnolias provides an excellent screen or hedge to block undesirable views or to define property lines. It can also be grown as an espalier against a wall, but be prepared to provide extra care needed to train and maintain the tree in the desired shape.
Southern magnolia can be grown in sun or shade. It prefers moist, well-drained, acidic soils. It is tolerant of high moisture levels and can be planted in areas prone to wet/dry fluctuations in soil moisture.
Container-grown Southern magnolias can be planted successfully any time of year. Balled-and burlapped trees are usually transplanted from August to October. Don't be alarmed if the tree sheds an unusually large number of leaves during the first growing season. Transplant shock is common with Southern magnolia.
If possible, dig the planting hole at least two times wider and as deep as the root ball.
Be certain the top of the root ball is level with the soil surface, then backfill with the native soil after breaking apart clods and removing stones or other debris. Water thoroughly to settle the soil.
Finally, apply three to five inches of mulch on the soil surface to conserve moisture and to prevent weeds. Wait until the tree is established and putting forth new growth before fertilizing.
In windy, exposed sites guy wires may be necessary to hold the tree in place during the first growing season. Place the wire inside a section of old garden hose before wrapping it around the tree to prevent girdling and injury to the trunk.
Once established, growth can be accelerated with light frequent applications of fertilizer during the first three growing seasons. Measure an area three times the canopy spread, then broadcast one pound (2 cups) of 8-8-8 or 10-10-10 fertilizer per 100 square feet in March, May, July and September. By the fourth growing season, reduce the application frequency to once or twice a year.
Some Southern Magnolias grow as single trunk trees while others, like 'Little Gem,' form multiple trunks. Begin shaping the plant while it is young by selectively thinning side branches as
needed to produce and maintain a pyramidal shape. Unless maintenance is a problem, leave lower branches intact to allow the canopy to spread all the way to the ground. This will help retain the natural form of the plant and will hide the old leaves when they shed in spring.
Dirr, Michael A. 1990. Manual of Woody Landscape Plants. Stipes Publishing Co., pp. 509-510.
| Table 1. Recommended Cultivars of Southern Magnolia | |
| 'Bracken's Brown Beauty' | Compact dense tree with pyramidal growth habit, reaching up to 30 feet at maturity. Lustrous dark green leaves with rusty brown back. Flowers 5-6 inches wide. Transplants easily with minimal leaf shed. Self-branching habit to form a dense canopy. |
| 'Claudia Wannamaker' | Dark green foliage with medium rusty brown undersides. Flowers at an early age. One of the most widely used new cultivars. |
| 'D.D. Blanchard' | Leathery, lustrous, dark green leaves with rich orange-brown undersides. In youth, the tree is more open than 'Bracken's Brown Beauty.' |
| 'Edith Bogue' | Among the most cold hardy of the magnolias. Tight pyramidal form, reaches 30 feet tall by 15 feet wide with narrow, lustrous dark green leaves. Loose and open growth habit when young, then becomes more dense with age. |
| 'Glen St. Mary' | Flowers at a young age. Lustrous, dark green leaves with bronze, felt-like underside. |
| 'Hasse' | Tight columnar form. Lustrous, dark green upper leaf surface, dark brown underneath. Ideal for small space. 40 feet tall by 15 feet wide. |
| 'Little Gem' | One of the smallest of the magnolias, reaching 20 feet in 20 years. Small dark green leaves with bronze-brown back. Flowers at a young age. Hardy to -5 degrees F. |
| 'Majestic Beauty' | Very little lustrous dark green leaves, profuse flowering. Reaching 50 feet with a 20-foot spread. |
| 'Margaret Davis' | Dark green leaves, brown back foliage, tight branching structure. |
| 'Russet' | Narrow leaves and upright pyramidal form. |
| 'Samuel Sommer' | Very dark green leaves with brownish-rust underside. Flowers and leaves are very small. |
| 'Symmes Select' | Lustrous leaves with dark brown back. Large white flowers on young tree. |
| 'Timeless Beauty' | Dense grower, large blooms 10 inches across. Upright branching, long bloom time. |
| 'Victoria' | Broad medium-size dark green leaves. Equal to 'Edith Bogue' in hardiness. No injury at -12 degrees F. |
The University of Georgia and Ft. Valley State College, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.
An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating.
Gale A. Buchanan, Dean and Director