I have some rosemary in a large flower pot that has been outside for about 5 years. I live in Zone 7. It has gotten to less than 10 degrees here and the plant is still doing great. We also had a foot of snow last year and it didn't harm the rosemary at all.
These plants seem to be very winter hardy to me. It seems to love the cold weather this time of year.
Well I have two that are winter hardy varieties coming to me this spring. Because I got all dreamy eyed from the last rosemary article that was written this past fall.
But seriously I am excited about getting them. I cut down a cranberry highbush to make room for one of the rose marys. It is okay the hgihbush was too big for the corner of my house plus I already had two starts from it in other locations.
As for as the rosemary Christmas tree is concerned. I always admired them and it feels like Christmas when Lowes gets them in.
Thanks for the hardiness reports! I now have two rosemaries but both are against a south facing wall so my zone 7 probably isn't truly Z7 there.
I can report that my rosemary Christmas tree that I put outside last winter did not survive.
One of my other rosemaries has become sort of sprawling and I found several nice rooted branches this fall that I potted up. One of them just might make it this summer as my first attempt at shaping my own Xmas tree. I read once that the growers of 'real' Christmas trees prune them by putting a sort of open, cone shaped gguide over them and cutting off whatever sticks out. Sounds easy.