If you ever want to spit something out of your mouth, bite into a trifoliate orange.
Going on memory, there are two species in China and one of them is more cold hardy. Both make inedible fruit though there are ways to separate the juice from the spit-out-da-mouf resin.
There is a very large patch of trifoliate orange trees about 40 miles south of Selma Alabama. This should get you to them. 32°06’25.2"N 87°05’40.9"W
They have 3 inch thorns that can puncture a tractor tire, the trees are somewhat invasive, and the fruit are not normally eaten by wildlife.
We also had this thread going for a while a few years ago. All Things Cold Hardy Citrus, news, thoughts and evaluations