Why do my peach trees get yellow leaves in the summer? This is zone 9. Soil is very sandy with crushed limestone bedrock about 1-2 feet down. I don't BELIEVE the roots are flooded, and I seem to get this even before heavy rains start. I get lots of growth in the spring, and fruiting is done before May starts. But as the summer season drags on, I lose a bunch of leaves to yellowing and browning, even while new growth is shooting out. The problem seems worse the older the trees get. FYI, they are grafted Florida variety - Tropic Beauty - so it shouldn't be a chill hours or obvious nematode thing. Additionally, I get weird growth and flowering patterns - with flowers appearing any time between fall and spring - I think that throws off the tree growth. I also add about 2 cups of 6-6-6 each spring per tree.
Is this normal? Do I have an issue? Is there anything I can do to help?