I have a plum tree in my new garden which is covered in plums but some of the leaves are shrivelling, any ideas what's wrong with it?
That looks like aphid damage to me. Not a lot you can do about it and a healthy tree will not be bothered by it.
Encourage ladybirds and bluetits to your garden - the bluetit fledglings hoover up the aphids in our garden.
Hoverflies also eat aphids, so planting lots of umbellifers that aphids love will encourage them into your garden too.
Thank you for the reply but what are umbellifers ?
Sorry, umbellifers are plant with flat heads of flowers like fennel, cow parsley, ammi majus, angelica etc
Hoverflies love them.