My ACER palmatum, which is about 25 yrs old, was potted until 5 yrs ago but is now in the ground and has been perfectly healthy until now. It looks about 75% dead. There are two beautiful branches and the rest look like sticks with an occasional very slim red growth but no leaves. Can you suggest a reason for this rapid decline and if it is possible to encourage it to regrow or is it a case of accepting the inevitable and starting again? M Lence
There are a few reasons for the branch die-back. It could simply be winter injury or maybe a fungal disease, such as verticillium wilt. Here are a few links on verticillium wilt that will aid you in diagnosing your tree:
In the meantime you should prune away the dead branches. You can verify the branches are dead by cutting a small sliver of bark from each branch in question - if it's tinged green it's alive and has hope of recovery, if it's tan it's dead and should be removed.
For information on a host of other japanese maple pests and diseases, please visit the following link: