If the inner needles on your Hinoki Cypress (Chamaecyparis) are suddenly turning from a healthy looking green to shades of yellow, orange and brownish-red in autumn, there is little need for concern. Needle shed is all part of a natural process. Each year evergreens will produce new foliage in spring and part of the preparation process involves shedding their older foliage in the previous fall. Shedding of needles and foliage is a 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 Chamaecyparis (Hinoki Cypress), Thuja (Arborvitae), fir, pine, cedar, 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.
The sudden change in temperatures over the past couple of weeks here in the northeast has caused some of the Hinoki Cypress to go through a major shed. I do have concern over this particular Hinoki, which I have had for over twenty years. It does tend to get more yellowing/browning over the others, but normally comes back with a flush of new growth in spring. If desired, lightly brushing the inner portion of the plant will help to remove the older browned foliage. If concerned about any particular branches on your plant, scrape the bark with your fingernail down to the growing layer. If the branches are brown and brittle the area tested has met its demise. If there is presence of a green growing layer underneath the surface of the bark, the branch is indeed alive.
Author: Lee@Landscape Design By Lee, 2019, All Rights Reserved