Cypress canker is really the only disease known to this conifer.
Although generally quite hardy, a canker infection can devastate an entire hedge and neighboring plants.
It tends to expand to the entire tree, and branches will start turning rust-colored and then die off one at a time.
Cypress leaves and branches turn brown, orange and dry off
No doubt about it: canker.
This is a microscopic fungus that sneaks in under the bark and can devastate entire forests – or hedges – of cypress.
Treating against cypress canker
Sadly, there isn’t any truly effective treatment against canker. Only controlling the spread is possible when it appears.
Cut any branch that has developed rust-colored blemishes at its base as soon as you detect the disease, and burn them.
Smart tip about cypress canker
It is preferable to be drastic and leave a scrawny cypress standing, than to hope against hope that it will go away: the only thing to go away will be more cypresses…
Canker starting on a twig by David L. Clement, University of Maryland, Bugwood.org under © CC BY-NC 3.0 US