Q.Stunted Plum Tree
I planted a triple grafted Plum tree in 2011. The only part of the tree that is growing is the area around the grafted scions, which now look like golf balls. The tree has flowered & produced fruitlets which I remove. The root stock looks very different to the Plum grafts which are Billington, Black Doris & Omega. Should I dig it out & start over with another tree?
I think you should try to figure out what's going on with the tree before you trash it. This article may give you some food for thought: https://www.gardeningknowhow.com/edible/fruits/plum/plum-tree-diseases.htm
Also, perhaps you could talk to the tree's grower, or the place where you bought it.