Mophead type hydrangeas are so prevalent in Pacific NW yards, novice gardeners may not realize there is another variety that is much better at withstanding hot summer sunshine. Panicle hydrangeas are often planted in all-day sun and have cone-shaped flowers that frequently start out white then gradually take on pink tones as the weather cools. 'Bombshell' Panicle Hydrangea is a compact version, growing two to three feet tall and three to four feet wide, with more white flowers per shrub than most other varieties. 'Bombshell' really doesn't require any pruning, but if needed, do it in the fall or late winter, as flowers will emerge on new wood.