Hydrangeas root easily from cuttings. Maybe, even just sticking them in some water, but this isn't the best way. The best way is to use a moist (not soggy) mixture of ½ peat moss and ½ perlite. Use semi-hard wood; new growth that has somewhat matured. Dip the cutting in rooting hormone, and stick in the mix.
This is Hydranges peegee. (paniculata grandiflora)
After you have put the cuttings in a pot, or tray, Put the whole thing in a clear plastic bag, and keep in a light spot, out of direct sunlight. Open, for an hour or so, every couple of days, to give them some air and check on moisture.
If you have a mist set-up, that works even better. Here's a mist system.
The mist comes on for 6 seconds, every 6 minutes, during daylight hours. Here it is, in operation. There are some hydrangeas, among others, in there.
