I have took cuttings all times of the year and rooted them (with root tone in powder form). I just keep them on the North side of my house in the shade and keep them well watered till I know they have rooted. First week or so they will wilt daily even with no sun. Then they are moved to the east side under a deck with limited morning sun till I feel good about them. You just want to plant them by early to mid fall to have a chance of getting thru winter. If you want faster/easier results you can take lower branches and bury them in the soil from the mother plant. They will root fast and will not wilt. Will have a much larger plant faster with no root tone involved. On more upright growing ones you may have to use a rock or stake to keep the branch from lifting out of the soil till it is rooted. Then in a few weeks when you have a good root system on that branch. Just cut it off the mother plant and put it in the yard where you want it. Keep it well watered just like any new hydrangea at first and you will love the results!!!

P.S. Propagation of Hydrangeas is nothing to be scared of....so easy to do. I say I have a success rating of 90% or better with cuttings. 100% with putting branches in soil. Last year I planted a cutting in Late Fall that I started in early Fall. With some mulch for help to get thru winter it made it and was the 1st year I havent made multiple plants. Just found a open little spot and gave it a try. It stands only about 6 inches or so tall so far this year. But it shot off a bud a couple weeks ago and I pinched it off to encourage growth. Then the the other day I noticed it shot 3 buds and I pinched those all back...lol...Now my yard is full of Hydrangeas and have no room to make anymore for myself. I will probably make a few or none this year. Because even my friends and family yards are full of Hydrangeas now.

Thanks for the advice. I think I'll try the burying method. Should I cut the skin or remove leaves or use bury it.

Thanks for the advice. Should I score the skin or remove leaves or just bury it as is?

In zone 5 I would grow your babies in 2-3gal pots for a couple years until they have a few thick enough stems to make it through winters. But yes, constant shade during the rooting process is key as well as continuous moisture. Cutting should simply contain a bud node and two small 2" long leaves, either natural or cut to length. Mist your leaves at least once every other day. Successful rooting is usually noted when the leaves retain their rigidity and the stem begins to grow longer.

how would you prep them for rooting?

When burying a branch I do nothing to prep it. Other than putting it a couple inches under the soil. When starting a cutting a take a razor blade and skin it. Then dip it into root tone.