I've accidentally left my rosemary out in 0F/-18C weather, and it looked fine. The bay tree sitting next to it lost all the new growth, but the rosemary didn't even lose that.

BTW, I don't even consider bringing in the rosemary until the forecast low is around 20F/-6C. It's happier outside, so leaving it out as much as possible is the goal.

The thyme is quite hardy. We had a light snow last week that it just shrugged off; brushed off the snow to snip some sprigs, it didn't look any worse for the wear. It'll eventually get beat up by frigid cold, but 20's F and it's fine. Sage, too.

I can't speak to rosemary. I've sometimes wondered if it's perennial in my zone. ?

I'll just drop in to point out, as I often do, that 'Arp' and 'Hill Hardy' or 'Madeline Hill' are NOT the hardiest rosemary cultivars, at least on the east coast. Since this myth seems to be persisting out there on the interwebs. It's the University of Georgia varieties like 'Blue Spire', 'Blue Spears', etc. that are hardier. 'Salem' too although I haven't personally tried that one. This is based on both my experience, and testing done at Well Sweep Herb farm. Still they are probably only 6b hardy, so don't get your hopes up!

I have a small potted rosemary that I brought inside already but maybe I should put it back out since it's been pretty warm for November.

I've seen some "cold hardy" varieties of rosemary online and thyme hardiness supposedly can vary quite a bit so I suppose you could move yours against the south side of you house, cover it and see what happens.

"move yours against the south side of you house, cover it and see what happens."

@christinmk z5b eastern WA, I am going to do just that today. Thank you.

Don't cover them up. The problem I have with rosemary inside during the winter is it doesn't get enough light. The *container* can be covered, but not the plants.

I think I/we are mixed up. I plan to leave the large herb container outside but I will do my best to shimmy it to be next to the house on the south side.

Nice to hear @beesneeds but key is...what hardiness zone are you in?

Oops. Sorry. Right now it's the tip of Lake Michigan zone 6, with minimun temps falling to 10-20F, with the occasional dips below 10. And generic rosemary from the garden center, no particular names other than "Rosemary", or "Upright Rosemary" if there was also "Prone Rosemary" being offered. Upright rosemary did better than the prone stuff.

The thyme here does it's own thing. I've planted some different kinds and colors over the years and it just keeps creeping out. Dies back a lot in the fall, leaves and snow cover it, and it comes on back in the spring. The oregano is a carpet too.

" Upright rosemary did better than the prone stuff. "

It's been my general observation that the trailing cultivars are not as hardy, unfortunately.

When you have your dips below 10F, is there usually complete snow over over the rosemary bushes?

I've had thyme for years in a spot where the soil is rather crappy, tends to be semi evergreen and always a few remain despite my tending to treat them as weeds, definitely is zone 3, though the beautiful variegated lemon thyme is a bit more tender that I tend to lose it, really should just heap a small pile of leaves upon it.

And there's a big difference between in ground plantings and containers. The former will be hardier.

And there's a big difference between in ground plantings and containers.

For sure.

So it will be an experiment with not much "repercussion" as I normally replace these herbs each year.

but I will do my best to shimmy it to be next to the house on the south side.

It has been shimmied ;). (The dead plant is/was a tender salvia).

"When you have your dips below 10F, is there usually complete snow over over the rosemary bushes?"

Not usually. I've done different stuff over the years to corral pots. A few years, had a pen of stacked straw bales. Some leaves around the pots, but the bales were taller than most of the plants, so provided a solid wind block. Other years, I've had pop up cold frames over my totes, and other smaller pots can be tucked in there. A couple years, they have been penned in the cold frame area, and the pots seated into leaves with the cold frames blocking the wind. I've had a couple years where I didn't really have a lot of pots for keeping outside, and the rosemary made it into the enclosed porch with some other plants.

Where the thyme and oregano is carpeted in sees snow. It usually gets some fall leaves enough to cover, not really trying to mulch them. They grow thick enough to mulch their own bases. In the winter when we get snow, there is an air stream that crests the hill there and tends to accumulate a snow drift. Since I know where that air stream hits, I set up my protected area inside that flow and up against the house. Since it's on the south side and in an air eddy of warmer, it's a nice niche for containers.

Out in the open garden areas... rosemary in pots did not do well in the open corral. It's an old dog kennel on slab. Great sun. The pots get packed in with leaves. But there can be a wind vortex in the drive area and it hits that corral. So while many things that die back do well there to overwinter, things with aerials that can be wind stripped don't so so well. In the ground with a good mulch of leaves before snows they did OK. But lavender does better in those spots. And a pot of rosemary is all I need. Last summer I didn't bother protecting, and this summer I didn't replace the plant. I have a lot dried, and still have some in the freezer.

(I have probably told this story before...I apologize in advance):

Several years ago I planted a "food" sage plant (I probably only used it when making stuffing/dressing for Thanksgiving). Anyways come November, cleaning up the containers I literally pulled the plant up by the scruff of the neck and threw it out of sight in the corner of the garden. It wasnt till the following season, sometime in the summer that I caught sight of it, reaching for the sun in this too shady locale, climbing through the chain link fence! I have never moved it. To see it each season I need to purposely search it out. It doesnt thrive as there is not enough sun but I do get enough leaves each October to make stuffing :).

Rouge that story reminds me of a Chamaerops - Med fan palm - I'd ordered from a notoriously awful Florida palm nursery in the mid 1990s. My very first ever attempt to grow a 'hardy palm'. It was supposed to be the purported hardier blue form from the Atlas mountains. Turns out it was green and totally infested with scale! There were no review sites back then of course...it took months for me to learn about their reputation via the original hardy palms board at insidetheweb and possibly gardenweb. And in fact I think I ordered in spring, paid with a credit card, and was told the plant wouldn't be ready until fall. In the months following, I learned of their reputation, and I came to regret ordering from them. I was so disgusted to have been had, I tossed it on our compost pile in the corner of the 1 acre lot. I can't even remember the name of the place but I do remember reading they went out of business in the early 2000s.

Lo and behold, in spring, it was still green! It had been probably covered by one more round of brush and grass clippings. But I left it.

Love these "survival" stories @UpperBayGardener (zone 7)!

I'm trying rosemary 'Arp" in-ground here in KY zone 7a. There are two pots of cutting-grown plants overwintering indoors as backup.

So while outside yesterday, I spotted for the first time a couple of flowers on this same unprotected rosemary plant. Amazing I say :).

Even more amazing that it's blooming. I still have quite a few plants with green leaves here even though we've gotten down to 20. No flowers though.

For sure @christinmk z5b eastern WA. TBH, I dont recall ever seeing flowers on previous rosemary plants that I have had.

Your rosemary in bloom is an unexpected treat!

Low temps in my area have been ~32 degrees overnight. My rosemary, sage, thyme and parsley are still going strong. I was happy they lasted until Thanksgiving as fresh-from-the-garden herbs made a huge difference for the dinner I cooked yesterday!

Where rosemary is completely hardy, winter and early spring is the usual bloom starting time. So although the overall survival may be a surprise, the bloom time is normal.

I don't give their blossoms much thought, but here in a climate that probably sometimes confuses them by being wetter in summer, they now seem to be in bloom for most of the year, with a peak in early to mid spring. They are also self-seeding.

the bloom time is normal.

And that explains why I have never seen it previously as up till this year I have disposed of my rosemary to the compost bin before November 1st.

(And I have never planted a purchased one outdoors till likely the first week of May)

A bit snow covered these days :)