I'm not sure where to post this. I used some curly willow twigs to help root hydrangea cuttings in water. Well, the hydrangeas did not root, but the willow twigs did. If I pot them up, where should I keep them during winter? They still have green leaves because they are indoors.
I would pot them up and keep them outside in a really well protected area for as long as possible making sure they don't freeze...or treat them as houseplants over the winter. They will have to grow their soil roots before they can be transplanted and can do that while in a sunny window inside.
Im not sure how many cuttings you have rooted but, how I do it is, make up a mixture of potting soil X 3 scoops, horticultural sand (from garden store) X 1 scoop, Pearlit X 1/2 scoop, mix together and take a bunch about 5-6 cuttings together and place in the soil mix, you may need to have a garden cane to support the tall cuttings but, by bunching the cuttings together, they normally support each other no problem.
Make sure you keep inside till they are filling the pots with proper roots, once the roots are growing well, empty the cuttings out from the pot and gently seperate the individual roots (try not to break any roots off. It may help to gently swish the rooted plants in a bucket of water as this will get rid of the soil and make division easier.
Pot up individually in a pot NOT TOO BIG, keep watering and when the weather next year is suitable, plant out either in rows or into larger pots and keep outside to harden off the rooted plants. Once you want to plant out into final position either as hedge or as shrubs, make sure you remove any Straight branches as these are strong and before you know they will weaken the twisted branches and take over the whole shrub in a couple of years, My plants are called curly walking sticks (Harry Lauder walking sticks, he was a famed Scottish comedian who carried one of those sticks) other people call them twisted Hazels, but they mature to have nice yellow catkins early spring.
like shaded conditions with gentle sunlight, plenty leaf-mold in the planting hole and as a mulch each autumn.
Good luck. hope you get good results.