in my notes on propagating plants, i have written that roots should be 1" long ... i remember reading this in a book on propagating plants; but it wasn't referring in particular to hydrangea; just plants in general ...

wow, you propagate hydrangea in water?? ... i have never tried that, but i have just about 100% success with layering & cuttings in soiless mixes ...

good luck, phyl

Thanks for the advice, Phyl. The roots are almost an inch now. The water rooting took almost 7 weeks!

I have pretty good success with water rooting. I have some that have gotten roots in about 3 weeks, usually a bit earlier in the summer. I have typically moved mine to 4" pots with either my typical potting soil (Miracle Grow Moisture Control) or a peat/perlite mix. I think the peat/perlite mix is probably the best way to go, but sometimes I get lazy and just use the potting soil.

The ones I've rooted this summer I potted up when the roots were around 1/4" in long and start them outside in full shade for part of the day. After a few days they are usually ready to be outside full time. I did have a few that needed extra TLC and spent more time indoors and being moved in and out and one that didn't seem to take at all and is back in water to grow more roots.

Thanks for the voice of experience, iechris. Mine were potted up today using the same potting soil you mentioned. It's so hot and humid here in south Louisiana that I'll definitely take your advise and keep them indoors a few days---then into full shade. 2 of the rooted cuttings are just green stems, no leaves. I'm hopeful they'll make the transition.
Thank you for taking the time to respond.