Black Spot and Root Rot are out so most likely you have a Magnesium Deficiency!
Go to the Dollar Store and get some (I can't spell it you soak your feet in it) ebsence salt
an-put 2 cups in a 5 gal. Bucket of water and stir. Then pore it away from the trunk, it's 100% Magnesium!
It want change the old leaves but it will the new growth!
After the winter every year! It'll be a darker Green too!
Go to the Dollar Store and get some (I can't spell it you soak your feet in it) ebsence salt
an-put 2 cups in a 5 gal. Bucket of water and stir. Then pore it away from the trunk, it's 100% Magnesium!
It want change the old leaves but it will the new growth!
After the winter every year! It'll be a darker Green too!