September is a bit late to start trying to root cuttings outside. If they are up close to the foundation of the home they may do okay outside and yes the jars will likely need to stay on all winter. Keep any eye on them during the warmer winter days and elevate one edge of the jar with a pencil or stick to let the heat out. You do not want them to get too warm and then freeze at night or it will kill them. Personally, I would dig them all up, place them in large pots and move them into a garage or basement for the winter. There they will stay cool and you can monitor the soils moisture better. Come Spring sit them outside during the day and bring in at night for a couple weeks. Then leave them outside for another week at night. Transplant back outside thereafter. You could gently check the roots at this time. If there are none, there likely will not be. I like the Olivia's Cloning Gel for starting/rooting cuttings. Seems to work very well>
Answered on October 3, 2015
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