Southern magnolias (Magnolia grandiflora) are native to North America and grow throughout the south. They are loved by gardeners for their glossy evergreen leaves, showy white flowers and ease of maintenance. The state tree of Mississippi, Southern magnolias are hardy in USDA plant hardiness zones 7 through 10. The tree grows moderately slowly, but can reach 80 feet high and 40 feet wide. Give this tree plenty of room or plant a dwarf variety, such as "Little Gem." The tree requires only minimal pruning and can be damaged by over-pruning.
Cut out dead, broken or diseased limbs in winter before new growth emerges. Use pruning shears for 1/2-inch limbs, loppers for branches 1/2 inch to 2 inches, and a pruning saw for larger branches. Cut the branches back to a healthy lateral branch.
Prune branches that form weak crotches. Magnolias have many small branches that may grow closely together, forming tight v-shaped growth (or crotches). These branches don't have enough room to grow adequately and eventually crowd each other out and break.
Trim back branches that droop to the ground to 2 feet above the ground or more. Cut the branches 1/4 inch beyond an outward-facing bud.
Cut large branches using a three-cut process. Make a 1-inch cut with a pruning saw 8 inches out from the trunk or large, lateral branch on the bottom of the branch. Make a 1-inch cut 3 inches further out on the upper side of the branch. Make a final cut through the branch at the collar of the tree, which is a small knobby protrusion where the branch meets the trunk. This process prevents the branch from ripping bark from the tree as it is cut, which can open the tree to disease.