Hi, could just be early onset of autumn, the weather we've had this year, the plants don't know whether it spring or autumn, that's assuming it hasn't been short of water, should be ok next year. Derek.

Your tree is fine. It's tired from producing all those plums and just wants to sleep. It will eventually drop all its leaves and go dormant until Spring. Hope the plums were tasty.

I'm not entirely convinced this is autumning - can you post another picture showing clearly some of the affected branches and leaves please? Is there any sign of brown or rust coloured areas underneath the leaves? Any obvious problem on the trunk or branches, like oozing or soft areas? Was the first thing you noticed wilting or drooping of the leaves, followed by browning or discolouring, or the other way around?