Most people expect to see changes in leaf color in deciduous trees and shrubs during the fall. But every year people call our office concerned when the leaves on certain evergreen plants begin to turn yellow with the change in the seasons. For many plants this is normal.
For example, azaleas may lose a few leaves now. These are the older leaves on the branches near the center of the plant. There is no need for alarm by the loss of a few older azalea leaves from now until spring.
However, if the younger leaves (those nearest the tip of the shoot) turn yellow or brown, there is cause for concern. Poor drainage, lack of water or alkaline soils may cause this condition. Be sure to keep azaleas and other ornamental plants well watered during dry weather that may occur from now through spring.
Other plants such as gardenias, hollies, camellias and cherry laurel may have yellowing leaves now. But as with azaleas, these are the older leaves on the stem near the center of the plant. The mature leaves will drop from the plant from now until spring. This is only the normal aging of older leaves. However, be careful to not confuse this normal process with spider mites, scale, lace bugs, nutrient deficiencies, poor growing conditions, salt injury, etc.
Just keep in mind that this normal change in leaf color and leaf drop occurs on older leaves generally during cooler weather–it’s a seasonal change.
Our lawns also experience some seasonal changes. The growth rate of lawn grasses decreases in the fall. Not only does this slowdown in growth mean less mowing is required, it also means that lawns will not be as attractive as they were during spring and summer. Weak, thinning and damaged areas of the lawn will show little to no improvement during this time because of this slowdown in growth.
Bermudagrass, centipedegrass and zoysiagrass will turn brown with the arrival of the first killing frost. Expect St. Augustinegrass to turn purplish as a result of cool temperatures and light frost. With freezing temperatures, St. Augustinegrass will turn brown in unprotected areas.