Shane, I don't have an answer whether or not Yuzu will grow outdoors during NC winters, so I wrote to a hardy citrus nurseryman, asking his opinion.
I also asked if Yuzu turns out to be hardy, should it be planted in the ground now or spring.

I also did a little research on Yuzus. Some people claim they do well in z7. The only problem is because it's a cold-hardy citrus, fruits are bitter tasting and seedy. I imagine very much like Poncirus.

Are you looking for a hardy citrus to eat or as ornementals? Toni

Thanks for checking this out for me. I am looking for something I can grow and use as a lemon substitute. I have read that yuzu has very good juice and can easily be used in place of lemon. I also understand that it ripens early which will be another issue in my zone 7 climate.

Hi Shane. Check out www.mckenzie-farms.com
Talk to Stan. He's a really nice guy, very informative and can help.
I told him about the Yuzu. He explained, though Yuzu is hardy to 5F degrees, that means, if temps occassionally drop down to 5F, a tree will survive, but if temperatures remain that cold for long periods, it'd be difficult if not impossible for a citrus to survive winter in those conditions.
Send Stan an email; I think he can help.

One of my citrus kicked the bucket last winter, but the stock did great..I HOPE it's Poncirus. It's planted in the garden, and going to stay out all winter.
Living in z5, it's almost impossible growing any citrus here, but I grew Poncirus before, it lived 4 years..That is until someone stepped and broke the entire top off..it never grew after that.
Good luck, Shane..have you considered growing citrus in containers? Toni

Now what fun would container growing be?

Shane how cold does it get there, I guess you could cover it with plastic or a blanket a few nights a year?

Frank

Our record all time low was minus 8 in 1985 but it is rare that it gets below 5 degrees in most winters but it does get down near zero on occasion though its rare and brief. I am looking for something that can be planted outside and survive the winter without much protection other than a thick layer of mulch. I am not really into container culture as this is too much of a hastle in winter.

Hi Thanks Shane and hope, yes I am my second season of growing citrus outside in my zone 5/6.... I do provide a TON of protection... Anyway this link is very interesting and provides some scientific data regarding cold hardiness, although not very encouraging.... I bet you can grow several varieties though if it seldom gets to 5 degrees

the link:http://www.walterreeves.com/uploads/pdf/coldcitrus.pdf

Frank, mind if I ask what type of citrus you grow in z5? Where are you located? Which state?
I'm in IL, and although I've grown Poncirus, like you, it took a lot of mulch in winter.
There's a guy in Chicago who grows Palm trees..One is huge. Imagine that, right in the heart of the city grows a tall Palm tree..
I planted some type of root stock this year..If it lives so be it, if not, it's ashame..I'd love for it to grow, even if it bears the most bitter fruit known to man.
So Frank, if you don't mind, please list your citrus.

Shane, I wish you luck.. If your area has short freezes, I'm sure you'll find something that fruits.
If I were you, I'd research various citrus this winter. It's probably too late to plant a young tree so late in the year. But as soon as all signs of frost is over and done, start digging a hole and amend soil.
I'll keep my eyes opened for hardier lemon trees. Some trees are much hardier than others..
I know a guy in Tx who keeps container citrus outdoors year round.
Did you ever hear of Acorn Springs? They're located in TX. www.acornsprings.com Check their site. Toni

For what it's worth, I planted a a little Yuzu from Stan last Fall here in Washington, DC (zone 7b/8a). It survived, but looked pretty ragged come spring. Don't remember what our record low for the winter was, 8-10F I'd guess. I certainly recommend protecting it the first few winters at least.

Hopefull, last winter I over wintered 7 citrus, 1 kumquat( which had great fruit in march)1 satsuma, 1 10 degree tang, 1 Taichang lemon, 1 changsha manderian and a tomville citraquat. They all survived with a LOT of attention. Essentually the roots were burried with heater cables and of course covered with plastic and blankets in the winter.... I can go into more detail if you are interested and dont think I am crazy.........It was a fair amount of work, but fun to walk around my yard and see the trees. I have pics if you like...
The low at my house was 0 f, some of the trees saw 25 f and the others 35 f.. ( 2 differnent areas)
Frank

I don't think it can survive 0 F but I know it can survive 10 F, although it sometimes doesn't do the best. They are completely unfazed down to 15-16 F.

Here's a picture of a Yuzu tree (growing outside unprotected) in the Nikitsky Botanical Garden in Crimea, zone 8b. That's about at the same latitude as Eugene, Oregon.

Yuzu can survive zone 8, but I don't think they can survive zone 7.

Although it's full of lots of seeds and therefore doesn't have much juice, one of the attributes about Yuzu is that it has relatively tender rind that's not really that bitter. For cooking purposes, you don't need to remove the rind (and in fact there won't be that much usable part of the fruit if you did).

It has its own unique flavor, more like sour orange, Satsuma mandarin, lemon mixed in, and a little hint of grapefruit to the aroma. The fruits are very aromatic, with a pungently deep spiciness. There's no other citrus that has quite the same aroma.

By the way, Yuzu tastes nothing like poncirus. It may be pretty sour like a lemon but it does have good flavor and finds use in Japanese cuisine.

I went to the Japanese market and put Yuzu extract juice on my fish, and have also used Yuzu salad dressing.