North American Pomona 14(2): 73 (April 1981)

A PEACH THAT SURVIVED 41° BELOW ZERO
Percy H. Wright Saskatoon, Saskatchewan, Canada

I received seed of the wild Manchurian peach about five years ago and grew several nice seedlings. They all froze to the ground during the winter of 1978-79 with the exception of two which showed no damage, even after 41° below zero. This year the trees have fruit buds and I am hopeful of seeing some fruit in August, though I don't expect the fruit to be large or flavorsome.


Letter to Peter Harris from Percy Wright, 1/24/1981

There are at least two bright spots, tho. One is that my seedlings of Manchurian peach are almost sure to survive the winter, and, if weather is favorable in blossom time, give me actual peaches next August.

The other is that we have discovered a new way to increase the hardiness of fruit trees. Graft a few branches of a superhardy variety, adapted to a short summer season, high in the structure of the tender variety one wants to grow. When the days shorten in mid-August, the leaves of the superhardy strain become aware of it, and send down a hormone to the roots that says, "Get ready for winter." When the root goes dormant, anything grafted on it, a dependent perforce, must go dormant too.


Subject: Re: [nafex] sandwiching, Ultra Hardy Peaches
From: Bernie Nikolai
Date: Wed, 9 Jan 2002 22:10:20 -0500 (EST)

Percy Wright was a famous horticulturist from the Canadian prairies who died about 15 or so years ago. What he stated was that only the peach trees that had super hardy Saskatchewan plums grafted into the peach tree survived a test winter in BC. The peach trees without any Saskatchewan plum grafts in/on them died, and he felt there was some interaction between the ultra hardy Saskatchewan plums and the peach trees that increased hardiness of the peach trees. He wasn't sure, but he thought it might have to do with the peach trees hardening off earlier.

Re: sandwiching, which is grafting a tender cultivar to a hardy frame tree, and then grafting a hardy cultivar to the end of the tender graft. So you might have something like Westcot apricot, Valiant peach, Westcot apricot, all on the same branch. Only the middle part of the branch would produce peaches, but the sandwiching would increase the hardiness of the peaches, in theory. I have tried this with apples and it worked fine. Mind you, non-sanwiched apples topworked to a hardy stembuilder also worked. Both survived fully for me. I originally intended to do this with peaches, but I could never get the peach graft to survive the first winter in my climate so I could "sandwich it" the following spring by grafting something very hardy to the end of the peach graft.

I have just recently come across an apparently legitimate peach that has been surviving and producing in Regina, Saskatchewan, zone 2B! The mother tree is several years old and has been producing for several years. The peaches are apparently of mediocre quality at best. They would never be a commercial variety. Nonetheles they are peaches, and they are edible, and they are ultra hardy. Regina can easily hit -40C and a bit colder. The mother tree is apparently a seedling from a planted peach pit. I'll try to get a bit of scionwood this spring and graft it onto a Nanking cherry I have.

Bernie Nikolai
Edmonton, Alberta


INCREASING APPLE CULTIVAR HARDINESS TO -40° F
Bernie Nikolai
Reprinted from Pomona, 25(4) Fall 1994

"Studies have repeatedly demonstrated the least hardy parts of a tree are the roots, the lower trunk, and the crotch angle of branches where they come out of the main trunk. If you bypass these tender-portions by grafting the tender varieties onto the hardy frame tree branches about six to twelve inches or so from where they come out of the main trunk (on a Dolgo Crab, for example), you may be astonished as to what will survive and produce for you if you live in a cold climate."

Michurin: Frost-resistant Peaches (1929)