A butterfly bush attracts not just butterflies, but also hummingbirds and bees. Its sweet-smelling flowers bloom from spring until the first frost in the fall. Butterfly bushes flower only on the current season's growth, which means that any limbs remaining from previous years will not bloom. Without trimming--or pruning--over time, your butterfly bush will become woody and blooms will be sparse. For this reason, a butterfly bush should be pruned every year, and late winter or early spring before new growth begins is the ideal time to do so.
Pinch off old spent blooms during the growing season to encourage more flowers.
Clean your pruning tools, such as sharp hand clippers or lopping shears, especially if you have pruned diseased plants with the same tools. Dip a rag in some rubbing alcohol and wipe the blades of your pruning tools down before you use them.
Remove the soil that you may have mounded around the crown of the plant for winter protection.
Trim back the entire bush within 2 to 3 inches of the ground. Make clean cuts. Do not rip the stems off--even just a little bit---to finish the cut.