Sounds like Poncirus (hardy orange). It's actually hardy into zone 6 and can grow into Pa., NJ., Conn., and a bit further on the coast. They are quite a thorny tree which is probably why we don't see them too much locally. There supposedly are recipes on line for what to do with their tardy fruit. You should be able to grow one if you really want one!

Brandywine, does the fruit have a nipple on the end and somewhat oval like a lemon? I have held a theory for many years there is a poncirus orange and lemon. The two poncirus "lemon" trees I knew of are both gone. I have the poncirus orange which is round like an orange. If it is lemon shaped, would you be interesting in trading lemon for orange seeds?

Google image search sez - poncirus it is.

I was wondering about the thorns and green stems on the tree.

I have never heard of this plant.

tsmith, the fruit is round. But it tastes like a lemon, smells like a lemon -- incredibly aromatic. The stuff I'm reading about poncirus says the fruit is inedible raw. But we've been using it in our iced tea for a couple days, and it tastes like lemon to me.

We are in zone 5. I wonder if I could grow this against our brick kitchen wall, which faces SE and provides a shield against cold coming down the slope from the NW.

Thanks!

Here is a link that might be useful: Raised by Wolves - in which I find a lemon in Virginia

The NC state university web site say they are hardy to zone 5. After the seedlings get a couple of years old, I would plant one or two outside and keep some inside to see what happens. The SE protected area sounds good. See the link below.

Here is a link that might be useful: NC State Ag School

Most of the Poncirus I've seen have way more seeds than the one you found. They are so full of seeds you can't squeeze much juice out of them. The fruit has a sticky resin under the peel that can be a pain to get off of metal or your hands, it also departs an odd taste to the juice or any jelly or other food made with them. It also taints the numerous hybrids out there in the quest for colder hardier citrus (it is truly hardy to zone 5). But, that resin has a brief period where it breaks down right before the fruit starts to rot. Maybe your timing was just right.

Plenty of people eat them, most often as marmalade.

I have some of these in the N. VA area. What is the possibility of grafting another citrus onto this plant. Will the graft keep the hardiness?

CharlieBoring:

Actually, they are often the best thing to graft citrus with. They will give you trees a little more toughness, but not enough for them to survive our winters.