I have 2 damson trees on my allotment . they fruit every 2 years should i prune them . if so at what time of the year would be the best ?
All plums ( which is what Damsons are a type of) should be pruned in Summer to avoid Silver leaf disease which may be prevalent in late Summer/Autumn.
We never have deliberately pruned our Damsons and they fruit most years depending on the weather.
I would try feeding yours first. They are actually quite heavy feeders. Organic material is good and then try a really good soaking with a high Potash fertiliser in later Winter.