Trees, Shrubs and Conifers: Maple tree problem - lack of iron?, 1 by jugglerguy

jugglerguy wrote:
I have a red maple (acer rubrum) that I planted about five years ago. It is sort of healthy, but the leaves are light green with dark green veins. Toward the end of summer the very top branches lose all of their leaves and die back. The tree is in northern Michigan in zone 5. It's planted in full sun in sand with about six inches of topsoil. I organically fertilize the lawn and water with an automatic sprinkler system.

Last summer I took a couple leaves to the nursery and he told me that it was a lack of iron. I bought some iron pellets and spread them around under the tree. Then I did some research and learned that if the soil isn't acidic enough the tree won't be able to take up the iron, so I added some sulfur to the soil because a soil test told me the soil was slightly alkaline. The tree showed no change. This summer, a different guy at the nursery suggested using liquid iron, so I bought some of that and added it three times this summer. The bottle recommended a very dilute dose, so maybe I should have used more. I think it was about two tablespoons each time mixed with water. Still no change. Any ideas?