Resin

If the tree is too large for its position, the best solution is to replace it. If you can't find a suitable replacement, you can plan on pruning properly every few years, which means removing tangled branches from the previous prune and cutting back others completely to try and reduce awkward regrowth. Wait until late summer to prune, there are too many fungal pathogens about immediately after flowering. The flowering display will probably be poor the following year as the tree re-establishes suitable flowering branches.

Subhirtella is a particularly poor candidate for pruning since it destroys the natural irregular shape and weeping form. If you don't like irregular and weeping shapes then there are plenty of cherries that grow in regular vase or round crown forms.