Hi MickyM please ignore the idiot above! He/she is a flamer and hopefully will get banned soon! I am sorry I don't have a solution to your plum tree problem. We have the opposite challenge too many plums and branches breaking off!

Does'e your tree get blossom in the spring Mickymaple?

Try pot ash.

Possible causes could be down to pruning, or were the blossoms killed off by frost, spring was early this year, so later frosts may be the cause.

Mick88's present vocabulary makes me wonder if he is also signed on as "Adolf"?

To address Mickymaple's problem, Blooming without fruiting is most often caused buy insufficient pollinators, such as bees, when it blooms, or a lack of compatible varieties of plum nearby. Lack of bloom may mean that the tree is still too young; it's not getting enough sun; bad weather, such as frost or high winds, just as the buds emerge; or yearly heavy pruning--plums bloom on wood 2-4 years old. I would check those problems, Micky, first.