|This article is of interest to the following WikiProjects:|
So inedible varieties is going to dominate this article, how much information should be supplied about specific varieties, subclasses. Poncirus trifoliate - Flying Dragon – Swamp Lemon. The pursuit of an edible hardy citrus is done primarily hobbies, any major companies or universities doing citrus breeding. Who is doing the work and what success or failure has there been? What are some of the challenges in producing edible fruit? Has DNA engendering been done? An antifreeze gene been added to any citrus? What varieties can with stand the lowest temperature Poncirus trifoliate, Australian desert lime? ~~
I'm going to try to do some work on this article - copy editing and sourcing.
I do recall reading a study conducted by the University of Georgia (within the last decade or two), which involved maintaining an experimental orchard of cold hardy citrus near Statesboro, GA. The goal was to maintain mature trees through 4 winters. The results were mixed, and interesting - it should be noted that among the 4 winters, one brought record-breaking cold into south Georgia, so the experiment probably bears repeating.
Nonetheless, the published study detailed what plants survived (satsuma and limequat performed best), and which did not (yuzus were killed during the first year, kumquats during the second).
This contradicts data from commercial growers, which would indicate that at least some of these plants can survive in the east as far north as central Georgia, and northeastern South Carolina, and on the west coast as far north as Northern California (farther north for the hardiest species and hybrids).
However here, personal data from individual growers, gardeners, or commercial orchards would qualify as original research, and will not qualify as a valid source for various reasons.
All of the above does suggest that the general truisms regarding cold-hardy citrus are generally accurate, but that a certain amount of 'range' in temperature tolerances exists in all of these species and hybrids: one yuzu may be able to take a winter in Wilmington, NC, while another yuzu of differing specific parentage (and thus genetics) may be killed swiftly.