In central USA it has been a hard winter. Local statistics show it was the worst since 1975. I remember 1975. In that spring, Dad sold his dairy. He said it had been the worst winter in his life.
January had record low temperatures week after week. Then February, usually our worst month, was warmer than usual, fooling some species of trees into starting to leaf out. Then March was colder than usual.
So my 7 or 8 year old Ponciris trifoliata from second generation Korean P. t didn't leaf out this spring. They were all dead to the ground. So after checking on them a few times, they are 6 miles from my home, I gave up on them. But yesterday I looked again. All but one of the have come up from the roots.
So It has been 50 years between two Ponciris-killer winters. And the new growth from roots shows that trees as hardy as pure Ponciris could produce fruit for several years before their tops are killed. And if on their own roots, they will come back.
Of course, this assumes weather will continue like the past, which is not a sure thing
As for my breeding stock. My thermostat got stuck on while I was at work. I came home to a house that was over 120 F. All my indoor plants died except a couple of cactus and a snake plant. All my citrus breeding stock were dead. They have been replaced. It wasn't cheap, though members of this forum were generous , charging less than I expected. And other plants were bought from dealers. These were more expensive, but a breeder has to have the right plants.
So I will continue trying to breed hardy edible citrus. Its what I do. I've lost a few years work, but that's life.
