Yes, here is a link to a page with instructions on how to propagate hydrangeas.

Here is a link that might be useful: Propagating hydrangeas

Not legally, but yes. :)

I just stick it in a well watered potting mix, lock it in a zip lock bag, and wait a month or so. Roots very easily. No need for rooting hormone, though it might speed up the process.

Thank you for all the info. I wondered about the "legality" but I hated to just throw it away if I could get it to grow.

If you have trouble out of these rotting when you put them in the zip/lock baggie, spray them with Daconcil. It has greatly improved my amount of successful cuttings.