In today's Newspaper DEADLY BUG THREATENING PARK TREES. Evidently Forestry Commission scientists have found Lawson cypress (Chamaecyparis lawsoniana), infected with Phythopbtors laterallis which is thought to have come from the US or Canada. How it got here has not been discovered yet. Any tree that gets the disease the leaves will change Colour from a normal olive green to a shade of olive grey, then wither and turn to reddish brown as the foliage and the tree dies. It seems to be spreading so beware. I do not know if it is prevalent in the US at the moment, but like Dutch elm disease disease which came from Canada, I am sure they will find out!
Regards.
Neil.