Last year I got 3 Hill Hardy rosemary plants from Richter's, after my old rosemary died, after a severe cold snap, and the wind blew the cover off of the hoop house. I couldn't get out to re-cover it, and it was gone in one night!
I planted two of the plants in the ground, and one in a 4 1/2 gal fabric pot, and the one in the pot took off! I figured that I would leave the ones in the ground in place, and when it got below 20º (the usual low limit for rosemary), I'd cover one with a trash can, and a brick or two, to weight it down, and leave the other uncovered, to see how resistant they really are.
Naturally, I forgot to cover one Sunday night, when it got down to 11º (maybe lower - that thermometer, though away from the house a ways, is on a brick post, so it may hold some heat), and only up to 16º all of Monday, with winds up to 35 mph., and back down to 14º Monday night!
Amazingly, both of the plants look fine! Not a hint of freeze damage, so this variety must really be cold resistant. I will still try to cover the one, if we have another cold spell like that. I did cover it on Thanksgiving - down to 16º , and the only other time this season that got in the teens.
The sage looks worse than the rosemary, but those can die back, and grow back, and I usually cut them down to the ground, once a cold snap does them in. I cut some of this off today, for a dish I just saw a recipe for.
IMG_20190123_120437972 by pepperhead212, on Flickr
Here is the one in the pot, which I even brought in from my back porch, wondering if it would get below 20 there (only got to 24º, turned out). Not a great photo, due to intense sun outside, but it shows the size of it, with a 5 gal pot next to it, for a reference size. And I have probably cut off at least as much as you see there, before I brought it into the porch, and since.
IMG_20190121_103422249_HDR by pepperhead212, on Flickr