What is wrong with my Cypress trees?

Question:

Our property has a row of Cypress trees that run most of the length of the property. They were planted before we bought the property, probably about 20 years ago. Some of them are looking very thin, and even those which seem to most healthy are beginning to look as though they may be too crowded. I am wondering how to best take care of them and would welcome any advice.

Answer:

Brian Erickson, Sustainable Agriculture Professional/Professional I

From one of the pictures it seems that the Cypress trees are not getting enough sunlight and are stuck in what is called the “stem exclusion stage” from the taller trees around them. One way to treat this is to remove the competing overstory that is blocking their sunlight exposure. As for the other pictures it is hard to tell what is affecting them. Here is a resource from Clemson Cooperative Extension that covers diseases and insects that commonly affect cypress.  Also, Diseases of Leyland Cypress in the Landscape, from University of Georgia Extension. Please feel free to reach out with any further questions.