I have a five foot wall about 3 feet from the magnolia tree. Now, the leaves are turning yellow. I wonder if there is any relationship between the wall and the tree. The garden center told me it was from the concrete leaching??? I don't know if he is correct.
Yellow Leaves on My Magnolia Tree
Certified GKH Gardening Expert
That could be possible, but only if the wall is relatively new, say just a few years old. If it is older than that, the chemicals in the concrete would have leached out long ago and be gone.
There are many things that can cause yellow leaves on a plant. This article should help you get some ideas on what could be affecting your tree: