Q: Should all flowers be deadheaded when they wither? Do I just cut off the dead bloom or snip the stem?
A: I think most plants look better when the dry flowers are removed. The usual method is to make your cut just above the leaves that grow below the faded flower. Some, but not all, plants will reward you by making more flowers at the new growing point. Removing butterfly bush flowers as they fade is a good way to keep this shrub blooming for months.