September 2014 – A GUIDE TO LANDSCAPE DESIGN & MAINTENANCE

If your evergreen’s inner needles are suddenly turning from a healthy looking green to shades of yellow, orange and brownish-red in late summer and fall there is little need for concern…it is all part of a natural process. Each year evergreens will produce new foliage in spring and they prepare by shedding their older foliage in the previous late summer and fall. Shedding of needles and foliage is a natural process that evergreens go through as a way of preparing for new growth once the weather warms. As the days become shorter and temperatures lower evergreens go through a slight dormant period similar to deciduous trees and shrubs. Many evergreens such as pine, cedar, Chamaecyparis (Hinoki Cypress), Thuja (Arborvitae), fir, hemlock and spruce lose some of their needles every year and may go through a major shedding every three to five years.

To examine, look at your tree carefully. Older foliage is shed first so the losses should generally be from the inside out and not at the tips. Prior to shedding the needles appear from green to yellow, orange and eventually brown, remaining on the tree until the process is complete.

The actual amount of needle shed on the tree or shrub varies depending on the growing season, temperature changes and amount of rainfall, and can sometimes be sudden. Often the change is unnoticeable but generally the drier the season or more drastic the temperature change the more noticeable the needle shed, a natural cleaning process leading to new growth in the spring.

needle shed fall — Fall Needle Shed on Evergreens Showing Previous Year’s Growth. Older Growth is closer towards trunk.

Other species of evergreens in the broadleaf category can also shed their leaves. Evergreens such as holly and laurel retain their leaves for only one year and rhododendron and azalea for one to two years. Leaves will appear yellow before falling but at some times may go unnoticed if new leaves conceal old foliage. This process usually occurs in spring when new growth is appearing but can happen at other times of the year as well. If the whole tree or entire sections of your conifer are turning brown then there is cause for concern and you should have a certified arborist or landscape professional examine it. Otherwise, fall yellowing or browning at the base or inner branches closer to the trunk seldom indicates a serious problem, but is more often part of the natural life cycle of the tree.