How to Prune South African sage wood?
Cut flowered growth back to strong young shoots below, removing up to a fifth of old stems near the base each year. Prune after flowering has finished.

South African sage wood · Buddleja salviifolia
Generally best grown by a warm, sunny wall in mild locations where it will produce better flowering. This South African species needs well-drained soil in full sun with shelter from cold winds. See buddleja cultivation for more detailed advice
Cut flowered growth back to strong young shoots below, removing up to a fifth of old stems near the base each year. Prune after flowering has finished.