Cypress trees turning brown from center out to the edge of branches
It is difficult to tell for sure from the pictures, but we saw a lot of winter injury in leyland cypress last season. Leyland cypress was recommended widely about 20 years ago, as a fast growing, evergreen landscape tree good for property lines and privacy screens. Over the past 20 years, the trees were planted too close together, they often grew together and became over-crowded. The crowded growth and maturity of the trees led to lack of air circulation, stress, and increased disease and insect pests. Bagworms are often a problem on leyland cypress. Leyland cypress is also very susceptible to winter injury with cold and wind damage. We have realized that leyland cypress does not re-grow a nice shape after pruning. Often we recommend that homeowners and landscapers remove every other tree to reduce crowding and stress.
There are a couple of plant diseases that affect leyland cypress, caused by opportunistic fungal pathogens. The management strategy is to prune or remove. Usually, I recommend that owners try to keep trees in good health and vigor, and try to avoid environmental stresses by planting properly and in good sites (not windy, good drainage), to avoid tree diseases.
Thank you for contacting Cooperative Extension,