When reading a question about butterfly bushes, your answer you said that pruning lateral stems is better. What do you mean by lateral stems on butterfly bushes?
Pruning Butterfly Bushes
Certified GKH Gardening Expert
Lateral stems are stems that grow out (horizontally) from the main stem. You can trim the terminal stems (those that grow up) if you want a bushier, shorter plant and the lateral stems if you want to help contain the width of the plant.