Hi, 2 of my 3 Nellie Stevens Holly trees have more yellow leaves than usual. I live just south of Baltimore Maryland. The trees are about six years old and it has been raining a lot this year. They are on a berm so they are not sitting in water. Do I need to fertilize and if so what kind?
There are several possible reasons for a greater amount of leaf yellowing on your hollies. Wet weather could cause foliar fungal diseases that may yellow leaves. (You usually will see brown or black spotting on the leaves, too, if this is the case. And the yellowing would be scattered throughout the canopy.) If only the oldest leaves are affected, it could be natural leaf loss. Although hollies are "evergreen", they lose their oldest leaves after several years. If the trees put on a lot of growth several years ago, but not as much in the last couple of years, you might be seeing a disproportionate amount of yellowing. In this instance, the yellowing should be confined to the interior portion of the tree. Yet another possibility for leaf yellowing is insect feeding. Check the trees closely for scale, spider mites, or other pests.