Buddlejas are beautiful, insect friendly plants. They're at home in most garden styles and will even thrive in a container but they sometimes get bad press for being unruly! The secret to keeping them compact and manageable is to prune them hard in February.
On established plants: Look for a strong bud low down on the main stem and cut just above it. This may look brutal but buddlejas make new growth very quickly. If your plant was cut back last season you'll see where the new growth has emerged so just prune to a bud at the same height as it was last year. Then watch the plant romp away with fresh new growth.
On new plants: Allow the plant to grow for a season, deadhead the spent flowers through the summer and begin to prune to shape next February.
Flower Fact Buddlejas get their Latin name to commemorate Reverend Adam Buddle, a Suffolk cleric and botanist who was born in 1662 and died in 1715. Knowing Reverend Buddle's name makes it easier to remember how to spell the plants Latin name! Correctly this has ja (Buddleja) at the end (but is also often spelled Buddlea).