Diagnosis
Diagnose: Japanese Maple Poor Fall Color
Use these observations to decide what to check next.
First decide whether the leaves are late, damaged, or early
If healthy flexible leaves are merely later or duller than expected, compare this autumn's nights, the cultivar's normal finish, and the bright and shaded sides of the canopy. If margins crisped in summer or leaves fell early, protect next year's leaf quality, but if one branch or one side colored weeks early with small leaves or dieback, inspect the root flare and trunk instead of trying to intensify pigment.