Hydrangea Paniculata Flower Seeds, Paniculata hydrangeas will grow and bloom in a wide variety of climates (hardy from USDA growing zones 3 to 7!). Unlike mopheads, they need several hours of sun to do well. If your weather is too cold to grow the pink and blue hydrangeas or if your landscape doesn't have much shade, consider growing one of the many types of paniculatas. North or south, we can all enjoy them.A desirable trait of all paniculatas is their tolerance for pruning. One can prune them at any time except when they begin forming bloom heads in the summer. The paniculata is the ONLY hydrangea that can be pruned into a tree form. Paniculatas often get very large. 8-10 feet tall and wide is not unusual. Some get even taller. A beautiful paniculata, and one of the most popular is 'Limelight' which can be grown in all parts of the United States except those areas which receive no freezing weather.