What Is Happening to a Young Magnolia Tree When Its Trunk Splits?

A young specimen of saucer magnolia in full bloom.

Gardeners relish adding magnolias to the landscape since they add a vibrant flowering display to spring or summer months. If a newly planted magnolia develops a splitting trunk, take action to reduce further environmental stresses to help the tree self-heal.

Significance

Young, newly planted trees are more susceptible to trunk splitting and cracking, according to Cornell University. Rarely does this injury cause death, but it does create a wound that diseases or insect could utilize to attack the plant.

Causes

Magnolias tend to exit winter dormancy early, beginning to flow sap up into the trunk and branches on warm late winter and early spring days. With wet tissues, subfreezing nighttime temperatures cause cells to expand as sap turns to ice. This is what leads to bark cracking or trunks splitting. Rapid changes of dry soil to overly wet conditions cause sap and cells to expand, too, and cause cracks and splits.

Prevention/Solution

Consider placing light-colored tree wrap around the trunk and primary magnolia branches from late fall until mid-spring. This shades the tree bark from winter sun, keeping the plant cooler and preventing premature sap flow when freezes still threaten. Irrigate the soil to keep it evenly moist from spring to fall, as well.

References

• Cornell University: Bark Splitting on Trees

Resources

• The United States National Arboretum: Magnolia Questions and Answers
• Magnolia Society International