Posted: 14/05/2017 at 06:22
Normally you would cut buddleia right back to knee height in March. As it's now mid May I would reduce half the branches to knee height and cut the rest back to a metre tall.
Give it a sprinkling of rose fertiliser or alternatively a watering with tomato feed and stand well back - it will put on lots of growth and soon be covered with blooms. If you remove each bloom as it turns brown you will encourage more flowers and prolong the blooming period.
In December cut the whole plant back to half it's height to prevent wind rock and consequent root damage.
Next March cut the whole plant back to knee height and feed.
Enjoy the butterflies