I hope to get some cuttings going this week of T-roses and a few climbers. I plan to put them in my unheated cold frame. It is situated near a continual stream of water (hot water heater outtake) and thought this will help keep the ground thawed through the winter. Do you think this will work in zone 5 (can get down to -20F)? Or do the cuttings have to be warmer through the winter?

Bernadette