I have a few JBP, some junis, bout 4 Colorado Blue Spricea and some other winter hardy plants in my poly house. All are on the ground and have no mulch on them. Now my night temps for the next 3 days is going to be down to -10 degrees out. Last year I had all my trees out in the same way but I really dont remember seeing -10 for 3 days straight. My garage is full. Are my trees ok?
It’s probably worth tossing something like old blankets around the pots/roots for the next few days
Even better, build a simple structure over the trees and cover it with blankets. It can as simple as some sticks driven into the ground. That will trap the ground heat around the trees.
Very nice upgraded advice Marty