Yellow Leaves of Magnolia Tree

Question

The leaves of my magnolia tree in my front yard have been turning yellow and falling off. About a month anda half ago, I began some hardscaping in my front yard. I have enclosed the tree with a 1 1/2 foot retaining wall,  about 5 foot in diameter. Also, I added more potting soil so I can plant more shrubs inside the wall. I lived in Temecula, southern California where the climate is dry and slightly warmer that the costal region. I have a regular sprinkler system that waters twice daily for 5 minutes. What could be causing this problem?

Answer 1

The roots are suffocating. Trees do not respond well to their roots being covered deeper than they naturally grow. The tree may get use to it, or it may die. There is a 50/50 chance either way. The only way to ensure it returns to good health is to remove the dirt that was placed over its roots.