I found Stan McKenzie's website a few nights ago, including a link to this forum, and his tree descriptions and pictures plus the stories I've read here have me very excited to explore what I can do with citrus.

I live about 30 miles west of Winston-Salem, about 60 miles north of Charlotte in North Carolina. In a typical winter we'll see low teens at the extreme. The last two winters have been unusually cold, though, and I saw the coldest temperature I've ever seen at 3F. There are only a few days each year, if that, where the daytime temperature doesn't get above freezing. We only get really cold when the skies are clear, which typically means lots of sunshine to warm things up during the days.

I did buy a trifoliate orange this past spring, and I'm planning on planting it this week. Is the fruit usable at all? My family and I grow or wild harvest/scavenge all the fruits and vegetables we eat, so we've been doing without citrus at all so far, so I'll be happy for whatever local conditions will permit, even if folks in warmer zones would despise it. Just a little zest for a dessert or a little juice for some mayonnaise would be a real treat.

Do I have any other options for superior quality or simply something different that I could just plant out in the open in my location? The south faces of most of my buildings are already taken up with other things, but I do have a spot on the south side of my house with some masonry around it, but I wouldn't want anything I planted there to get more than 6-7' tall. I'd love to hear recommendations!

Could I open up any more options if I just threw a large blanket over trees on the nights when it's supposed to get down below 20? And maybe put some large water containers around the trees? (But what do I do if they freeze solid?) I don't think I want to go to the trouble of supplemental heat or misting systems. (I might also consider some potted options I could move indoors, but I'll save those questions for later.)

I'd love to get in touch with anyone nearby that has any citrus trees (and maybe even come visit). I travel to Raleigh and up I-85 into Virginia occasionally, and also head south toward Charlotte or the sandhills every so often, plus all around the NW corner of the state.

*Link Fixed* I would start with a book called hardy citrus you can order it here: http://www.sepalms.org/SPS_Publications.htm . I was recommended this book and love it.

Just to let anyone know who is cleaning Trifiata, the juice is like glue. If you don't use gloves you will be sorry. I use automotive Brake cleaner to remove the junk when I get it on my hands...

Hello,
There are some reports on edible poncirus growing wildly in NC close to Wilmington.

link

Not sure that is still there, since very limited data on it are available.
It is closer to the ocean and more to the South than your place, but if it is true poncirus and not a hybrid it should grow well at your place.

Eatable Poncirus is just someones daydream. = Millet (462-)

They might be edible with a severe cold so you couldn't taste it much.

I'm roughly 100 miles South West of you in the the upper corner of North Georgia near the NC state line.

I have about 7 Poncirus trees planted in my yard, and they are completely hardy. I even had some in pots last year that I left outside and froze SOLID, and still lived afterward. Trust me, Poncirus is easy. Mine are not old enough to fruit yet, so I can't help you on the taste. If mine are to horrible to process and eat somehow, The plants are still very ornamental and the fruits could be used for aroma therapy or paint remover or something...

My lowest temps have been around 11F on a couple of nights a year.

As for planting something in the open or somewhat protected that might be useful, you might want to read up on the Thomasville Citrangequat (Stan M. has them) I've seen quite a few reports that say they are edible fresh and ripe and useful in recipes.

If you want something really delicious you will have to be quite a bit more involved in protection schemes.
If you are willing to spend a little time every year preparing for winter, then I would highly recommend Owari Satsuma mandarin trees. I have two and they have survived undamaged for a couple of years now, though I do build a cold frame over them and use temperature activated lamps on the coldest nights inside the shelter.

I would say kumquats would be just a bit more hardy than Satsuma.

I know you said you were not really interested in supplemental heating, though this may be necessary on the coldest of nights given your zone.
If you build a South facing structure with some good thermal mass you might be able to store enough sun heat on winter days to get you through most if not all nights, but that really would depend on your methods.

Some passive heating and protection methods:

1. Jugs/barrels of water. Paint dark. Water freezing releases energy in the form of heat. (The will thaw out the next day.
2. Cold frames/greenhouses. Even a little teepee of poles and plastic sheet would make a structure adequate for many situations.
3. Concrete/brick/rock/boulders Thermal mass like this will heat up in the day and release heat at night.
4. Earth/dirt pushing a pile of dirt up around the stem and over the graft union will be good protection for at least the lower part of a tree.
Another way to use the Earth is to build a partially underground greenhouse or dig into a South facing hillside. The earth maintains a pretty constant temperature year round.
5. Water plants before a hard freeze. This will keep the roots from freezing and prevent dessication by cold dry winter winds.

When I started getting interested in growing citrus a few years back, I was obsessed with trying to make it easy as possible, but with time I've realize that anything worth having involves some work.
The truth is, caring for my various citrus trees, tweaking my shelters, etc has become one of my favorite hobbies.

You say that you are 30 miles west of Winston Salem. I would imaging that your weather is very similar. You could get away with growing Citrange or Citrumelo in your area. Here is a link to a nearby grower who has been growing and selling Citrumelo from seeds taken from a tree in Winston Salem, that I understand is older than 20 years. I have read that the flavor is like a grapefruit that has been picked early.

http://www.chillypalmtree.com/CITRUMELO.html

Ilya, I don't know anything about the Swamp Lemon. It sounds like a variety that I would not be interest in. There are a lot of citrus varieties (especially crosses) that don't have much to offer. Millet (465-)

There pretty much is nothing, unless you protect it.

So what would you all say are (1) the cold-hardiest minimally edible (i.e. better than nothing in the absence of any other citrus) fresh eating citrus and (2) the cold-hardiest citrus that's not necessarily fit for eating straight but could be used for citrus-ade or to give some other kind of food a little citrus flavor?

Ilya, "eatable" is in the taste of the beholder. Citrus varieties that are held as being non-eatable by the general public at large, will still be found to be eatable to somebody some where. Over the years, I have thrown away as many, or perhaps more, citrus trees than I have kept, due to the quality of fruit they produce. If a tree does not produce a good tasting fruit, I'm not interested to provide the effort a citrus tree deserves. Each to their own, others have different preferences. Thats why they make Fords and Chevrolets. - Millet (465-)

I think the most cold hardy citrus I would actually put in my mouth would be Changsha mandarin. Anything else is good for looks, but not eating...

http://citrus.forumup.org/about2412-citrus.html