Cutting faded flowers off plants in order to generate more blooms or bushier growth is called deadheading. Most blooming perennial and annual plants benefit from this practice because it prevents the plant from using its energy to create seed. Deadheading not only extends the bloom period, but the life of the plant can be extended because some plants die after they produce seed. The Butterfly Bush, or Buddleia, is a flowering perennial shrub that is famous for its ability to attract large numbers of butterflies to its colorful flower spikes. Proper deadheading keeps the plant in good shape and helps the plant produce several cycles of blooms throughout the growing season.
Cut off individual blooms after the bloom fades and turns brown but before the seeds are formed. The stem on which the flowers were blooming should be cut back by one-third of its length. Cut back at a point one-quarter inch above a leaf node or an area where a set of leaves are growing from the stem. It is OK to cut the stems back further if needed than one-third to shape the plant. The plant will generate new growth and blooms from the pruned area.
Cut back the entire plant after a bloom period if you were not able to cut each individual bloom as it faded. In this case, use garden loppers, if needed, because they cut larger branches easily and cleanly. If it is still during the growing season, or at least six weeks before freezing weather arrives, cut back the entire plant by one-third to one-half to generate a new round of blooms. Cut the largest limbs back to a main limb or to the ground and cut the smaller limbs by cutting one-quarter inch above a leaf node at the desired height.
Cut the plant to the ground after frost. In areas where the weather does not freeze, cut the Butterfly Bush to the ground in late fall anyway. This generates new growth and more blooms when the foliage returns in the spring or during the next growing season.