Replenish organic mulch as needed. Do not apply inorganic fertilizers near trunk. Do not use fertilizers containing herbicides. Powdery mildew, a gray mold which appears on the surface of the leaves, is best controlled using mildew-resistant varieties. Control sooty mold by controlling aphids.
Control aphids with approved insecticide or biological controls.
Remove aggressive vines that shade and weaken canopy. Study branches before pruning. Establish strong framework. Prune for safety whenever needed. Remove thin twigs and stems from base lower trunk.