Why do leaves on evergreens turn yellow?
Broadleaf evergreens drop old interior leaves that have been shaded by new growth, resulting in a yellowish/brown color that you may be noticing.
Depending on the species of plant, evergreen leaves generally last 1 to 6 years, with a percentage of leaves falling off every year.
An infestation of sap-feeding insects can suck the life out of a plant, causing leaves to turn yellow and drop off.
It is useful to become familiar with your evergreens’ normal leaf drop renewal cycle. That will make easier to pick up on abnormal shedding caused by extreme heat or cold, wet or drought, nutrient deficiency, insect infestation, disease and pollution.
It is normal for older leaves to turn yellow and drop off in the early spring before new growth starts, but it is worsened by exposure to stress from the environment and pests. Be sure to be on the lookout for insect pests, disease and environmental stresses that cause unnatural leaf drop.
Examples of Yellow Evergreen Leaves:
