By Dan Gill
LSU AgCenter Horticulturist
(11/16/18) Fall is the best time to add hardy trees to your landscape here in Louisiana. If you are thinking about adding shade trees, small spring- or summer-flowering trees or trees for screening, head out to local nurseries and purchase and plant trees in the next few weeks. The Southern magnolia is a popular choice.
The Southern magnolia (Magnolia grandiflora) is well known as a traditional tree for Louisiana landscapes. Like camellias, azaleas and crape myrtles, it is often considered essential for creating a “Southern” style garden. Unlike camellias, azaleas and crape myrtles, however, which are all native to the Far East, the Southern magnolia is native to Louisiana and the Southeast.
Southern magnolias are rather large-growing trees that can reach well over 60 feet tall. But on average, trees tend to be around 40 to 50 feet tall with a spread of 20 to 30 feet. This means that you need a fair amount of room in your landscape to accommodate this tree.
The Louisiana Super Plants selection for fall 2018 provides a solution for this problem. The Little Gem magnolia (Magnolia grandiflora Little Gem) is a dwarf-growing cultivar that stays significantly smaller than the standard Southern magnolia. They typically grow about 8 to 10 feet wide and 20 to 25 feet tall.
One of the remarkable things about Southern magnolias, including Little Gem, is that they retain their foliage year round, while most magnolia species around the world are deciduous. And what outstanding foliage it is. The foliage of Little Gem is deep green and lustrous. The leaves are about 6 inches long and have attractive rusty brown undersides. This evergreen habit is most noticeable in winter when the green foliage, along with other broadleaf evergreen trees such as live oaks and hollies, provides welcome relief to the bare, leafless branches of deciduous trees.
The flowering of the Little Gem magnolia is one of the outstanding characteristics of this tree. At about 6 inches across, the size of the white flowers is slightly smaller than standard magnolias, but the fragrance is just as intense. They stand out beautifully against the dark green foliage. The Southern magnolia is the state flower of Louisiana.
Flowers generally appear in greatest abundance beginning in late April, peaking in May and diminishing in early June. But Little Gem magnolia trees reliably continue to flower sporadically through the summer, and flowers often appear as late as September or October. Overall, they bloom more and later than standard Southern magnolias. The lemony fragrance of magnolia flowers fills the sultry summer air and is intoxicating if you stick your nose right into a flower and take a whiff.
Left to grow on its own, Little Gem magnolia trees will retain their lower branches, creating a canopy that starts at ground level. This is generally not practical when growing standard Southern magnolias because their spread is so wide they would take up way too much room. But because the spread of Little Gem magnolias is only about 8 feet, this is more of an option. Little Gem trees allowed to grow this way are effective as a hedge or screen when planted in a row. You also have the option to gradually remove the lower branches as a young tree grows taller. Continue to do this until the canopy is as high as you need it to be, generally about 8 feet from the ground.
Little Gem magnolias are best planted from November through March while the weather is cool and while the plants are dormant. Magnolia roots are very sensitive to the depth of plantings, so it is critical that the top of the root ball be at or slightly above the surrounding soil.
Dig the planting hole as deep as the root ball and two or three times as wide. Remove the tree from the container, and place it in the bottom of the hole. Thoroughly pulverize the soil that was removed to make the hole, and use that soil, without any addition, to fill in around the root ball. Water the area thoroughly to settle the soil and apply 2 to 4 inches of mulch over the area of bare soil.
If planted too deeply or in a location not to their liking, magnolia trees tend to grow poorly and stay stunted. A happy well-established young tree, on the other hand, will grow moderately fast, especially if fertilized in spring each year.
Be aware that even though it is evergreen, magnolias drop leaves abundantly in spring and early summer. They also drop old petals when they are in bloom and seed cones in late summer and fall. Large standard magnolias can be messy as a result. The smaller size of the Little Gem, however, means less leaf litter to deal with. Still, it’s best to locate these trees away from pools where stuff dropping out of the tree will not be a major nuisance.
Initially, Southern magnolias have an upright pyramidal habit when young, which gradually changes into a broader canopy with a rounded top as trees age. But the Little Gem magnolia tends to keep a columnar shape through its life.
The Louisiana Super Plants program is an LSU AgCenter educational and plant promotion program that highlights tough, reliable and beautiful plants for Louisiana gardeners. Louisiana Super Plants selections have a history of outstanding performance in Louisiana landscapes or have proven superior in years of research plant trials. Louisiana Super Plants are university tested and industry approved.
Little Gem is a Southern magnolia that does well in Louisiana and has been named a Louisiana Super Plant. Photo by Dan Gill/LSU AgCenter