Leyland Cypresses disease suspected

Asked July 6, 2017, 8:37 PM EDT

I have 12 beautiful (they were) cypresses that maybe a year or two ago were affected by the bug. We didn't know what to do so, we wait, some of the branches became dried but new branches cane out. Recently my HOA asked me to prune them because they were growing into the side walk and bother people. I am busy single mom, who lost her dear husband last year who was taking care of everything so I hired the company that mown my lawn to prune the trees. As a result the cypresses are now turning more and more brown. They look awful and I am asking for help. Thank you if you can give me advice. Best Gianpiera

Howard County Maryland trees and shrubs disease issues trees

1 Response

Leyland cypresses are, unfortunately, susceptible to disease and pest problems. They can can also get winter injury, which can cause branch die-back. (https://extension.umd.edu/news/brown-leyland-cypress-winter-damage)

Seiridium canker is a very common fungal disease in Leyland cypresses. The small browning tips will eventually drop out. You can also prune out larger branches that have died back. There are no fungicides that are effective for this disease. Here is further information about it: https://extension.umd.edu/hgic/plants/seiridium-and-botryosphaeria-canker-leylands-trees
The best you can do is keep the plants well watered during drought periods and prune out dead branches.