Butterfly bush - Prune in the early spring with the onset of new growth. Can be pruned back to about a foot. It should be noted that butterfly bush is invasive. See our website. You may want to take the opportunity to plant a native plant in its place. http://extension.umd.edu/hgic/topics/butterfly-bush
Russian sage - generally plants are cut back to about 6 inches above the ground annually in the spring. New buds break fro these low woody stems.
Caryopteris - prune in late winter to early spring. Flowers are borne on new growth of the season.