February is the best time to prune your Butterly Bush in the south. We are in zone 7B so if you live in the north you may want to prune them a little later, They bloom on new wood so in order for your shrub to be full of blooms, it is best to cut them back when they are dormant, right before spring arrives and new growth begins. The Buddleia comes in many sizes and colors. They are drought tolerant and love the heat. This plant is a great pollinator also, but it is most loved for how it attracts many varieties into your yard.