By Wormhead
United Kingdom 
I have a Plum tree that I planted seven years ago, It is a self pollinating plum, but I am only seeing one plum on the whole of the tree, this is the second year this has happened, can anybody give me an explanation to why this is happening?
8 Sep, 2016
Before you do anything, did the tree produce blossom in the spring? If yes, then was the blossom, killed off by early frosts or perhaps picked off my birds. If no, then have you pruned the tree in the hope of encouragement? If you think none of these things happened, then I would give the tree one more chance so why not give the tree a good feed of high potash feed, (it is a little late but worth a try). Give it one more chance next year and if still no fruit then I would start again with a different variety. (A reasonably new variety which is a Victoria substitute and more reliable is Jubilee; give it a Google search).
8 Sep, 2016