"I found out recently that rosemary is only supposed to be hardy in zones 9 and 10. I live in zone 8, "
Bitbit, there are many rosemary varieties hardy to zone 7, some even claim to be hardy to zone 6. "Hardy Hill" would be a good one for you but the absolute best would be ARP, no doubt about it.
Kevin, rosemary tends to get woody stems after about 2 or 3 years, depending on the variety. You can trim it back but best to do it by thirds and let it take its time adjusting.
Shoe