I have a very large (and old) hydrangea that thrives and blooms beautifully. This year, there is foliage up to 50 - 60% of the wood but the tops of the stocks seem dried and dead. Can I prune these to where the new foliage is?
There's a good chance that your hydrangea was affected by the hard winter. Pruning would probably help it alot. Here's an article that should help you: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/prune-hydrangea-bushes-hydrangea-pruning-instructions.htm