Magnolia grandiflora is an evergreen tree that is classified within the Magnoliaceae plant family. The tall tree has a pyramidal shape and fragrant white flowers. It is used as a shade tree or as a specimen tree, and it is commonly planted along streets. Several insects feed on the leaves of Magnolia grandiflora including aphids and scales. Fungal spores can also infect the tree and cause leaf spot.
The plant genus Magnolia is named after the late 16th century French botanist Pierre Magnol, and the species name grandiflora is derived from the Latin words grandis and flor, which translate to "big" and "flower" respectively. Commonly, the Magnolia grandiflora is called the southern magnolia or bull bay. This species has over 100 cultivars, or varieties. Bracken's brown beauty and Edith Bogue are considered the most cold-tolerant cultivars of Magnolia grandiflora.
Magnolia grandiflora is native to the United States. It populates the coastal areas from North Carolina to central Florida and west to Texas. It typically grows near streams or swamps.
This tree generally grows 60-90 feet (18-27 m) in height and spreads 30-50 feet (9-15 m). The trunk is about 2-3 feet (0.6-0.9 m) in diameter. The broad, branching tree has dark green leaves that are glossy on the top and rough on the bottom.
The flowers of this tree bloom in the spring and summer. They are large and showy, typically growing to 12 inches (30 cm) in diameter. The flowers grow singly and are shaped like saucers.
This tree produces a reddish-brown fruit that is shaped like a cone and bright red seeds. The fruit matures by September, and it attracts birds. By the fall, abundant amounts of discarded fruit and dried leaves cover the ground beneath the tree.
The southern magnolia grows best in well-draining, acidic soil that is fertile. It can tolerate drought conditions once established. The area should be exposed to direct sunlight, but the tree will thrive in partial shade.
It is recommended to spray insecticidal soap to reduce aphid and scale infestation. Aphids are pear-shaped insects that feed on the leaves and secret a sticky residue residue that attracts mold spores. Scales are tiny insects which suck the sap out of branches and leaves.
Another concern with this tree is leaf spot, which is a fungal disease. The symptoms include brown or black spots on leaves, which eventually causes the leaves to fall. Spraying a fungicide will prevent the disease from spreading to other parts of the tree.