Of all the varieties of plums, the Damson plum requires the least amount of pruning. Before getting out your loppers, set your mind to the fact that unless your tree hasn't been pruned before and has grown wildly for several seasons, you will be cutting very little. When it comes to pruning your Damson plum, this is one time when less is definitely more.
Prune your Damson plum in the winter or very early spring before new growth has begun. This will encourage your tree to put on a healthy crop of plums.
Remove any dead branches or any branches which appear diseased. Cut back to the trunk or at least 4 inches into good (living) wood.
Remove all branches that cross each other or that touch.
Remove branches that grow across the center of the tree and any branches that grow downward.
Remove any suckers which grow from the roots of which grow out of the trunk of the tree. Suckers do not have bark and can usually be pulled off the tree easily by hand.
Rake up and remove all rotting fruit that is on the ground and any dead or diseased wood you have removed from the tree.