I have taken cuttings of penstemon, salvia hot lips and hydrangea. I have them growing in pots with a polythene bag covering them. They seem to have rooted well now. However I’m not sure what I should do next to keep them healthy through the winter. Should I remove the bags? Where should I overwinter them? I don’t have a greenhouse. Many thanks for you help.
If they have rooted, remove the plastic bag, they should do fine outside whilst it's still warm. Keep them somewhere shaded until it gets colder, then look into getting a cloche/cover and fleece for the winter time.
Otherwise - you'll be chasing it down the road on the first windy day
If you like taking cuttings, it's worth investing in a cold frame. They're relatively easy to make too, if you're handy with a saw and screwdriver. You can even just rig up some bricks/blocks and a piece of polycarbonate for a lid to do a temporary job up against a house wall
I live in west central Scotland - not where that photo is...