Yes, 7a/b is about the limit, ARPARP is a cold hardier variety. But the thing with Rosemary in an eastern zone 7a/b is NOT so much the cold it is the excessive WET soils and summer HUMIDITY! Raised beds, excellent drainage, full sun, and air flow will all help!

P.S, I used to have lovely evergreen bushes here in Zone 7a/b NJ, over the last decade or so, summer humidity and excessive rains have killed them off.ARP

This one doesn’t get lots of heat since it is in the mountains. I love the natural look of it. I do kind of want to grow some back home in zone 6.

Over the past two years I've tried it twice, you cannot grow rosemary in a container in zone 7. I have, reliably, had it come back over multiple years in the ground. It is very borderline here.

You would probably need a hardier type like Arp or Hills Hardy or Alcalde that are supposedly hardy in zone 6.

This one seems that it survived -2 in 2022. It looks beautiful for that freeze.

ARP is hardy to at least -10F in the ground as long as it is planted in a properly prepared site. If grown in a container in zones lower than 8, it will need winter protection

I’m surprised it’s survived. It’s planted in heavy southern red clay that holds lots of moisture and it does get somewhat hot and humid in the summer.

Thirty years ago, I gave my MIL a rosemary plant. She planted it in the ground in Staten Island. Last I knew, it was still there. I bought it from a good nursery outside Philadelphia, and it may very well have been Arp. I bought one for me at the same time, and grew it in a pot for about 25 years. Then it got too big to bother hauling inside and out. Currently, I have one that's only three years old.

I'm in zone 6, and have had rosemary grow in the ground and hold in pots outside over winter. But it depends on the microclimate on where in the yard. In the kitchen garden it's OK... across the yard where it's not quite the same and they fail. Lavender grows in those areas much better.

That may very well be my "problem" (it was more an experiment since it thrives in the ground), it's on the deck with a large air space under it. I'm sure it holds in cold air pretty well. Probably surrounded it with cold air since it's an upper deck. I bet it would do well in a pot some other place, but this deck is adjacent to my kitchen. Hence, the reason I have potted herbs on it. Mint also hates it on the deck?! Weird, but true.

P.S. I may double pot new pots of mint and rosemary with styrofoam peanuts inbetween. They're so close to making it, I think this could be the factor to make it work. Thanks for getting my old mind to churning.