D.D. Blanchard is a cultivar of the Southern magnolia tree (Magnolia grandiflora). This particular evergreen tree is an especially hardy, fast-growing magnolia, reaching heights of 50 feet or more and bursting in the spring with large, fragrant, creamy-white flowers. The leaves are equally showy, featuring very dark green tops--possibly the darkest green of any magnolia, according to Cherry Lake Tree Farm--with orange or rust-colored undersides that are frequently turned towards the sun.
The Blanchard Southern magnolia is a warm-climate magnolia. It is not cold-hardy, but grows very well in some of the hotter climates in the South. This tree grows best in United States Department of Agriculture (USDA) growing zones seven through 10B, according to the University of Florida.
Magnolia trees in general grow best in full sunlight or morning sun followed by some dappled afternoon shade, and the Blanchard is no exception to this rule. Plant your Blanchard Southern magnolia in a location where it will be exposed to a minimum of six hours of sunlight per day.
Soil and Water
D.D. Blanchard magnolia trees are quite adaptable to a wide range of soil types, according to the University of Florida, as long as they are sufficiently moist. These trees need a lot of water and really grow best in consistently moist, loamy soil. They can survive periods of flooding but not extended periods of hot, dry weather. In such cases, supplemental watering is necessary for the tree to flourish.
Pruning is not necessary for Blanchard magnolia trees to retain their pyramidal shape, but the limbs do grow very low to the ground, which can be a nuisance in pedestrian areas. In addition, some leaves and the fruit do drop from the tree, even in evergreens, creating some litter. For these reasons, many home gardeners prune off the lowest branches in order to effectively clean up the area around the tree or create space for people to walk underneath it.
Acidic soil is important for the Blanchard magnolia if it is to thrive. While these trees will grow in poor soil, they do best if fertilized with an acidic fertilizer. A thick layer of organic mulch consisting of leaf mold or peat moss works well. Apply it in the spring and extend it to the edge of the tree's canopy. Or, sprinkle a slow-release, water-soluble acidic fertilizer on top of the tree's root zone in early spring.