How to Prune large-flowered St John's wort?
Usually little pruning is needed. Lightly shape if necessary, removing dead, damaged or diseased shoots. Prune after flowering.

large-flowered St John's wort · Hypericum kouytchense
Grows well in moist but well-drained soil in sun or partial shade
Usually little pruning is needed. Lightly shape if necessary, removing dead, damaged or diseased shoots. Prune after flowering.