Summer Blooming Butterfly Bush
A frequently asked question: “When do I prune?” For general shaping, or for evergreens, the answer is: “Almost whenever the need arises.” With flowering shrubbery, one needs to be more specific.
For early bloomers like forsythia and lilac, general pruning needs to be done right after flowering because next year’s blossoms are formed on this year’s wood. Furthermore, remove older stems to keep the shrub flowering more vigorously.
For summer bloomers, like potentilla, crepe myrtle and butterfly bush, their blossoms are formed on current season’s new growth. They should be pruned while dormant or just before new growth begins in the early spring.
Hydrangeas present a bit of a challenge. One must know if it is a mophead (pictured), a rebloomer, or a paniculata variety. Mopheads bloom in late spring to early summer. Blossoms appear on old wood and thus must be pruned by late summer.
Rebloomers blossom in summer to late summer. Flowers appear on both old wood and new, so they can be pruned anytime, still producing blossoms. Large shrub paniculata bloom on new wood, and can be pruned up to just before flowering.