Mature trees, shrubs and perennials dying
We have a mature garden in Sheffield planted with a wide range of trees, shrubs and other perennials that normally thrive. The garden is on clay and drainage is not brilliant but this has not been a problem in previous years.
In the last few months we have seen a large number of mature plants begin to die. Usually the process begins with leaves curling up at their edges and progresses to loss of leaves and death of the plants. The plants are growing in a number of different beds and most beds are affected.
Plants that have been affected include a Eucalyptus tree, a mature Acer Japonica, a large bay tree, an entire row of mature lavendar plants, sage, box, rose bushes, hydrangea, clematis, kiwi, jasmine.
We have a polytunnel in which a mature vine is affected, and also tomatoes and peppers, which normally grow well in this environment, are seriously stunted or have died.
We have just noticed that the leaves on a very mature Ash tree in school grounds adjacent to our garden are starting to turn. We have checked with immediate neighbours and at least one further tree outside the perimeter of our garden seems to be affected in a similar way.
There are some species that are unaffected, including geranium.
From reading other threads on this forum and the RHS's page on Honey Fungus, https://www.rhs.org.uk/advice/profile?PID=180, I fear that this may be the culprit. In the main, the lists of susceptible and resilient plants seems to match our experience. One exception is box which is on the RHS's resilient list, yet we have a number of plants that are affected.
Attached are some illustrative photos - can anyone confirm this diagnosis?
If Honey Fungus is the cause, how is the infection likely to have been introduced? Is there anything practical that can be done to protect plants that currently appear unaffected?
Any advice gratefully received.