I bought a plant several years ago, propagated it with cuttings. Last year I spent the summer in NY, my neighbor dug up the plants, put them around her house. I've since taken cuttings from those plants to repopulate my yard.
The plants have taken several cold seasons, with a few frosts each year. This January we had a couple of weeks of nightly hard freezes, 20-25 degrees. All plants are still growing just fine.
Seed the Mind, Harvest Ideas.
In my experience, rosemary will survive down to nearly zero for short periods outside. If you can keep your greenhouse in the high twenties, rosemary should do just fine. And be sure to try a prostrate form as well as an upright. For some reason, the prostrates bloom earlier - I had one that routinely cranked up in January (in the Willamette Valley). A very welcome sight!
When I was working in retail nursery, cold tolerance varied among varieties, with trailing varieties being less hardy, and the more wild upright varieties less so.. the most cold tolerant advertised 15 deg F. We had a string of nights in the teens this last fall. New transplants died. Several more established plants have severe damage windward, but survived. I think that is the edge of their tolerance.
Paul Cereghino- Stewardship Institute Maritime Temperate Coniferous Rainforest - Mild Wet Winter, Dry Summer
Hey Seth, are you in Missoula? IF so, there is a guy selling rosemary at the Clark Fork Market that is zone 5. He is also selling really huge rosemary plants (couple of feet high) that he has overwintered. He'd be a great person to talk to about the whole overwintering thing.
Also, I don't know how well it's going to do, but I just bought a zone 5 fig tree, Chicago Hardy. See how it goes...
i have read that the brown turkey fig might do ok in a greenhouse here..also in the Wayside garden catalog there was a hardy orange, said hardy to zone 5..I'm not sure if that would make it in an unheated greenhouse in our area or not..i'm still kicking around the idea of giving it a try???
I may try it and the brown turkey fig next year..but i still have plans to move my greenhouse this weekend to a new location (over the buried pex in my ground that runs the heated water from the wood boiler in the winter, the ground never froze where that pex was buried all winter long here..so we thought that might be a good location to move the greenhouse to)
Bloom where you are planted.
Whatever you say buddy! And I believe this tiny ad too: