Q: Some of my Gardenia bushes have yellow leaves. Is this an
iron deficiency ? What do you recommend ? A: It is common in
spring to see yellow leaves on gardenia, holly and Southern
magnolia. The phenomenon is caused by the plant moving food
resources out to new growth on the branch tips, leaving interior
leaves to survive as best they can. The weakened yellow leaves
may get spots from fungi taking advantage of them but the
disease rarely moves to other parts of the plant. If the yellow
leaves are several inches back from the branch tips, and if the
tip leaves are green, your plant is reacting normally. It will
look fine in a few weeks. Spraying with fungicide or fertilizing
will not help the situation, it’s just a part of the lifecycle
of the plant.