Greenhorns Blog reader John D. Galuska, Ph.D., followed up our post on the cold-hearty Asian citrus the Yuzu, by sending us some pictures and information about the Flying Dragon fruit. The Flying Dragon is a dwarf cultivar of Trifolate orange, native to China and Korea, and supposedly hearty to USDA zone 6. Galuska, who runs Grown In Town Farmstead in Bloomington, IN, writes:

I’ve been growing Flying Dragon at my urban farm in Bloomington, Indiana for about 6 years (outside year round in Zone 6). The photos I’ve attached are from one of the larger trees I have now. It had a great deal of fruit this year and seems to be thriving. I know of only a few other growers who have mature Flying Dragon trees in Indiana, but the word is spreading.

There are a few other reports of this citrus around the internet. By some accounts, it is not very tasty, but but there are people out there that use it for a variety of things including a citrus-ade, marmalade, allergy-aid, and syrups.
Do you grow a cold-heart citrus or other rare fruits? We'd love to keep hearing from readers who are pioneering rare fruit varieties in their communities and bio-zones.