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Every year my plum tree bears lots of fruit. Nearly ever year the leaves look shrived and it looks unwell but still gives loads of fruit.
This year the leaves look even worse, loads have fallen off and their is not one plum or baby plum on it?
Just a bad year for it, will it bounce back next year?
Are they newly planted?
Plum trees suffer from aphids abuse which will cause the leaves to curl.
If they are newly planted they could be short on water too.
Could be honey fungus... Check for symptoms. (Google)
Default problem for plums pruned at the wrong time of year is Silverleaf.
Scroll down this for more info.
http://www.kenmuir.co.uk/index.php?route=information/information&information_id=25
Are the leaves crumpled but green up at the shoot tips, or shriveled and off colour all over?
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I don't know if it's any help but our plum tree is looking very healthy with lots of fruit. It's a different type though so your mileage may vary.
Looks like the regrowth or later growth is good, but the earlier leaves had that leaf-curling aphid. It should have moved on by now, and there's not much you can do anyway, apart from TLC. And if you aren't on a limey soil, a handful of coarse oystershell grit scattered on the soil around. It might like that. People feed it to chickens, you buy it loose from that sort of shop.
It looks a bit dense in the middle, you might want to thin it in late summer, taking out crossing branches and ones growing inwards. Not much, a fifth or so, to avoid a big shock to the tree. You need to know about cutting at the collar, and the safe way of cutting without ripping the bark downwards.
I'm in Leeds and this year, all the plum and greengage trees have been decimated. I'm told it's aphids (as mentioned above) but I've not looked into it. They look as through they've had petrol poured on them and torched.
Cheers slowoldgit, sound advice and will prune late summer.
Oh, and check for oozing sticky stuff where branches fork and suchlike, plum canker...
https://www.rhs.org.uk/advice/profile?PID=86
(scroll down a bit)