Mention hydrangea and the big, pom-pom mophead (H. macrophylla) variety is what generally comes to mind. There is a hardier variety, though, with blooms that, while not huge and round, are just as attractive as the mopheads: Hydrangea paniculata. Pinky Winky is an H. paniculata cultivar that prolifically bears 12- to 16-inch long flowers. The blooms begin white and eventually turn bicolour, with areas that darken to pink. One of the easiest hydrangeas to care for, Pinky Winky isn't particular about soil or climate and isn't as water-dependent as its cousin, the mophead. Pinky Winky is hardy to U.S. Department of Agriculture zones 3 through 8 and blooms from midsummer until frost.
Grow the Pinky Winky in either full sun or partial shade.
Water the Pinky Winky slowly and deeply, when the top 2 inches of soil is dry. During periods of drought and particularly hot weather, water once a week.
Place a 3-inch layer of mulch around the hydrangea. Keep it at least 2 inches from the trunk and spread it completely around the plant, out to the dripline. Rake it back in the spring and apply a fresh layer after fertilising.
Fertilise Pinky Winky in early spring with a slow-release fertiliser formulated for shrubs. Use the rate suggested on the label and spread it 2 inches away from the trunk to the farthest reaches of the branches. Water the top 3 inches of soil after fertilising.
Prune the hydrangea in early spring by cutting out any branches that are crossing over others and any dead stems. Cut any growth that does not contribute to the overall form you desire. Pinky Winky generally doesn't require annual pruning yet is tolerant of even heavy pruning so don't be afraid that you will hurt the plant.