We don’t do any pruning of any types of hydrangeas in late summer or fall. Big leaf, mountain and oak leaf hydrangeas set their flowers in the summer for the next year. So we don’t prune those at all ideally. If we really must, it’s best to prune when the flowers open in the summertime. Plant these types of hydrangeas where they can grow into their full size so you don’t need to prune them. Smooth leaf hydrangeas, like Annabelle and incredible, and pinnacle type hydrangeas like lime, light and q