potting some elderberry, hardwood set on heat mats in the

potting some elderberry, hardwood set on heat mats in the root cellar, so damp and even temps. this set rooted in 2 weeks, the rest are about 50/50 so maybe another week. rooting grapes in the same way this year, pots of well draining mix, 8000ppm ima talc and bottom heat. after potting, the elderberry are a bit droopy so set them under timed mist for a while. everyone starts hardwood cuttings a bit different, the easy method is stick in the ground. well this works only if you have the right climate and local environment, and soil. could I just set them in pots outside, maybe but even in a cool cellar they're sending up top growth without roots, so it would have to be very early in the year. elderberry is very borderline in zone 3, still looking for the most cold hardy ones.