valleylynn said:Mine have just gone through 6°F for about a week, with up and down temps since. They are sending up blooms now. They are both cold and drought tolerant for me.
This is in a pot, Lynn? Its very true that there will be no (or little) damage to blooming hybrid hellebores
in the ground at prolonged 6°F. Does your ground even freeze in zone 8b?
Horseshoe said:I'd also recommend the plants be kept moist. A dry root ball will freeze and zap --- there go the feeder roots if not more. Best to keep the roots moist, especially in nursery pots 'cause there is no insulation.
An opposing view from a more northerly clime: while a plant may look worse from a bit of dehydration, it's quite amazing how well they survive in cold temps.
A bit of dehydration concentrates the chemical to water ratio, and lowers the freezing threshold of the plant, making it more tolerant to cold temperature. As for a dry root ball freezing [apparently faster] than a wet one, there are two considerations: 1) water conducts heat faster, so it will also cool faster, and 2) water contains more "heat" energy than air, so it has more stored "heat" energy to lose. How these two phenomena interact, I am not sure. I can only say for here in the north, winter dry (frozen water is considered dry as it is not available to the plant) is better.
