A native plant, Oakleaf Hydrangea is a handsome, cold-hardy deciduous shrub with large, white pyramidal flowers (technically, inflorescences) in the summer and foliage shaped like oak leaves. Oakleaf Hydrangea is the only member of the Hydrangea family with leaves that turn shades of deep red to purple in the fall. Winter reveals exfoliating, cinnamon-colored bark. Because Oakleaf Hydrangeas bloom on old wood, any pruning should take place after blooming to preserve next year's buds.  Host to larvae of the Zebra Swallowtail Butterfly.