my plum tree is in full blossom, but has a lot of blossom free new branches shooting up at the top, I want to keep it from getting too big, can I safely prune this new growth or should I wait?
I think plums like cherry are liable to get silver leaf disease if pruned in the wetter parts of the year so the usual advice is to wait until summer for pruning them.
It's winter when you definitely don't want to be pruning your plum tree, because it's then that the silver leaf spores are around. If it's a young tree you can prune it in April, as the buds are bursting, but July is the recommended time for older trees. https://www.rhs.org.uk/fruit/plums/pruning is worth a look.
Since 2019 I've lived in east Clare, in the west of Ireland.
Posts
https://www.rhs.org.uk/fruit/plums/pruning
is worth a look.