I have white powdery substance with stringy fibres in soil in a very dry shady spot underneath Cherry Laurel trees. It is spreading and nothing will grow where it has established itself(apart from the Cherry laurels already in situ. New/young transplanted cherry laurels will not grow but shrivel and dry out). When it rains heavily mushrooms grow.
I live in the West Midlands in Britain and all advice I have found refers to damp mould and treatment by drying out the soil. My soil is bone dry so drying out is pointless.
Can anyone advise how to rid myself of this substance before it kills all my plants?