Hydrangeas are one of my most favorite flowers and it is so sad to me that they last such a short time. But one day I discovered that I could dry them and keep them for a long, long time.
I've since experimented with different methods of drying them, but I always come back to my original method because it works the best for me. Here is what I do:
I cut several blooms first thing in the morning and shake them upside down to get out as much yard crud as possible.
Then I pull off all the leaves except one nearest the blossom. The leaves aren't all that pretty when they dry, and they usually get in the way of bunching the dried blooms in a vase or pot. So they come off.
Next I clip them upside down to clothespins or bull clips. I have a magnetic knife strip behind the wood fascia trim over my kitchen sink. I keep bull clips on it, and this is my primary place to hang my hydrangea blossoms.
Or, I clip them to skirt hangers and hang them on the closet rod. They hang there about three days and then they are dry: