The damson is a flowering plum tree that grows in the UK's temperate climate. While sometimes mistaken for a standard plum tree, the damson is an ancestor of the European plum and is classified botanically as a separate species. Damson plum trees can reach a height of 6 metres (20 feet), with dwarf damson plums topping out at 3 metres (10 feet). The damson plum shows fragrant white blossoms in April that give way to delicate purple plums. Damson plums can be sweet or sour and are excellent in pies, jams, tarts and chutneys.
Check the branches of your damson plum tree for signs of dead, diseased or damaged branches. Diseased or damaged branches will display wounds or blotches on the bark, while dead branches will feel hollow to the touch and may have other cosmetic differences from healthy wood.
Cut off all dead, diseased or damaged wood using lopping shears. Remove the wood at the intersection with the main branch or trunk and carry all pieces to a garden waste bin or compost heap far away from the site. Disinfect your pruning tools before continuing.
Remove interior branches that rub up against other branches, since friction will eventually cause one of them to break. Also prune away older wood that no longer bears fruit. Prune away weak, tiny branches that will not support the weight of developing fruit.
Trim off branches that grow at a downward angle. Also trim away upward-growing branches that make a 70 to 90-degree angle with the ground.
Thin out the interior canopy to allow more light and air to circulate. This helps prevent disease and aids in ripening the damson plums.
Thin out the fruit when it reaches the size of a cherry. Remove all but two or three damsons from a cluster of developing fruit so the branches don't snap under the weight of too much fruit. Thinning fruit also improves the flavour of the fruit left on the tree.
The best time to prune is in early spring once frost danger has passed for your area.