The magnolia tree is a large, broad-leaf evergreen with a trunk that can reach a diameter of 2 to 3 feet. Mature trees are difficult to transplant, as the root system is rope-like with few offshoot branches, allowing it to spread wider than most trees. Magnolia trees with a trunk diameter smaller than 4 inches have the best chance of being moved via transplanting into a new location. Choose to transplant the tree during the dormant season of late fall or early spring for best results.
Prepare the new planting location by testing the soil pH two weeks prior to planting. Verify the soil is acidic with a pH of 3.5 to 7.0. Work ground rock sulfur into the soil to lower the pH if needed. Water the area well to assist with absorption and let it rest for at least two weeks.
Dig around the root ball of the magnolia tree, starting at the outer edge of the drip line. The drip line is the area of soil below the end of branch growth on the tree crown. Prune roots that extend past the drip line to easily pull the tree out of the ground. The roots of the Magnolia grow long instead of deep. Pry the root ball out of the ground with several planks and gently set the tree on a tarp to move it to the new planting location.
Prune roots that are close to the trunk to prevent them from girdling the tree. Cut through roots that are circling the root ball and near the soil surface. This will stimulate new, strong root growth.
Dig a hole in the new planting area that is twice as wide and the same depth as the root ball. Amend the removed soil by working equal parts of organic compost. This will increase the nutrient value and water-draining properties.
Set the tree into the hole making sure the top of the root ball is at ground level. Fill half of the hole with soil and water well to compact it around the root ball. Fill the remaining hole area with soil and gently pack in place to eliminate air pockets around the roots.
Water the tree generously after planting to compact the soil around the root ball and stimulate root growth. Continue to water the tree weekly to keep the soil moist but not wet.