MENUYellow leaves detract from a landscape even though yellow is a leaf’s natural color. When they’re alive and making food, chlorophyll masks the yellow pigment.
Many people ask me what to do about yellow leaves. It’s one of those questions in which the answer is, “It depends.”
If the plant is a spring flowering bulb like a tulip or daffodil, yellow leaves have done what they’re supposed to for the season and should be removed. Removing these dead leaves will cause the plant to direct nutrients to any remaining green leaves so they can continue making food to be sent to the bulb for storage until it’s needed next spring.
As annuals get close to their life end, leaves may start turning yellow. This also happens when plants don’t get enough water. Removing yellow leaves when you deadhead the flowers will cause the plant to redirect nutrients to the green leaves where they will create, through photosynthesis, the energy the plant needs to create new flowers and, possibly, new leaves as well. Of course, they will need that all important inch of water per week to stay healthy. If yellowing continues, the plant has reached the end of its life and will have to be replaced.
Yellowing leaves on perennials and woody plants like trees and shrubs could indicate insufficient moisture, insects, or disease attack. Begin by making sure the plants are getting enough water. If leaves continue to yellow, I recommend an inspection by one of our Plant Health Care (PHC) professionals. Don’t remove yellow leaves from these plants. Leave them on the plant or on the ground where they fell to help our PHC professional make an accurate diagnosis. If the plant is suffering from a pest infestation, you don’t want to throw these leaves in the compost heap. Bag them and put them out with the trash, and then disinfect your tools before using them again.
You won’t see yellow needles on conifers like juniper or yews, but you may see brown. It could be winter burn if you didn’t apply antidesiccant or it may be a fungus. Our PHC professionals will be able to tell you which. Whichever the cause, the action is the same – remove the affected branches. But be careful that you don’t disfigure the plant.
I won’t get into a discussion of yellow or brown turf at this time, except to say it may be caused by a pest. But more likely, it’s the grass’ natural protective reaction to go dormant in excessive heat and drought.
