I live in Central Valley, CA so I don't experience true freezes. But it's 8a,8b,9a range where our freezes are 25'ish a couple times in winter. There are varieties of citrus that can stand colder weather -- but what is usually discussed is the upper foliage and fruit. Any of them in typically sized containers are going to suffer root loss if unprotected below 30F weather, which can severely compound the problem if even lower. Unless you are burying the entire pot in-ground (or creating a giant mulch mound around it), it is best to continue your practice with relocating the citrus of the extreme cold. If you are asking about in-ground plantings, the satsuma mandarin is supposed to be very cold hardy, so are kumquats, and many lemons will regrow the canopy if the rootstock was protected adequately (much easier than protecting the entire tree) during rare freezes. However, you might visit this link to check out his opinions about cold hardy citrus, esp from WA folks asking about it. He thinks it's a myth. Here is a link that might be useful: Cold hardy Citrus a Myth?

Perhaps try asking at the place of purchase about it, or googling? Doesn't seem to be anyone on here right now with any experience with it.

bought a finger lime from a nursery in march. potted in 25gal pot. kept in on the patio, used same fertilizer as for lemon, avocado and tangerine trees but smaller amt. it had only a few buds which fell off with first stiff patio breezes. Nursery guy said it'd be done budding for the year: boo hoo. But about a month and some cool weather later, about 34 buds popped out and fruited. Hot, hot weather spurt started browning the leaves and I read that in Australia they like a canopy so I moved it under a shade tree (filtered light) which it seemed to like much better...no more browning leaves. But I watered it and all but 15 fruit fell off. I pampered it which is hard to do when you don't know what you're doing. Now it's July 15 and suddenly there are tons of buds again! Weather is cool for this time of year and perhaps it's being fooled into thinking it's springtime again. I can't believe it's budded three times though, and I just bought it in March. So far, no mature fruit bud the tiny 1/2" fruits are still hanging on there.

And, W&N will prune their Carrizo to "standard" lollipop shapes, which is also part of the "standard" definition. Other growers will market Carrizo as "semi-dwarfing" and not prune. If you read the last page of the "California Citrus Rootstocks" booklet produced by UC Riverside, you will see they categorize both Troyer and Carrizo as inferring a "medium" tree size. Swingle is small, C35 is small, C32 large, Volk as med/large (it can get VERY large here on my property) and Macro as medium (but betting that's not the case for John, who has ideal growing conditions for Macrophylla rootstock - his trees are big and get big, very fast). I don't think I would consider 6.5 acidic, but within the neutral range (6.5 to 7.5). Carrizo and Troyer are essentially indistinguishable, so what I say for Carrizo would apply to Troyer. You'll see most growers are starting to favor C35 now, due to size constraints, more precocious,produce fruit faster, as well as they are more tolerant to phytophthora. C32 is a full sized, standard rootstock. Spent some time talking to the curators of the Riverside Citrus Park, and they shared that most commercial growers are switching over to trees on C35. I agree - Carrizo has not fared as well in my yard as the trees on C35, due to my heavy phytophthora issues. But, if I can keep the tree alive, it will eventually mature enough to overcome any phytophthora issues, which I found rather interesting. Patty S. This post was edited by hoosierquilt on Tue, Aug 26, 14 at 14:28