Snowball Hydrangea (Hydrangea arborescens) is a good choice for colder climates since it flowers on the current season’s growth ("new wood") and is not bothered by late spring frosts. They produce large round flower heads that remain attractive into fall. Most gardeners cut the stems to the ground in late winter. New shoots emerge from the base of plants in spring and bloom the same summer. Plants tolerate light shade as well.