sicetaitsimple wrote:
I think that we should not confuse "hardiness", generally defined by resistance to severe cold, and "productivity" in such and such a climate, being a fruit tree.
That the tree does not burst is a good thing, but usually we expect fruit! And there is not necessarily won for varieties a little exotic in climates that are not.
I am not a tree specialist, but I do not think that the "cold" in winter has a great influence on productivity, except:
a) the tree breaks, its trunk bursts, etc ... (the olive trees in many regions during the winter 53, for example)
b) frosts at the flowering / fruiting stage ... (this 21 April, for example)
So a tree that will "survive" the very cold (those that we meet once every 10 or 20 years) will generally produce ...
Or, if it does not produce, there may be, in the case of exotic plants, other factors: cross-pollination necessary but impossible for lack of an acolyte in the corner, absence of a specific pollinator, photoperiod ( influence of the length of the day / night) ...