Any luck with zone 4/5 hardiness in zone 3?
I'm waiting for this global warming thing to get zone 4 up this far North, but in the meantime....
What was the biggest zone stretch you ever tried for fruit trees and bushes and how did it work?
If your experiment was successful, what extra effort did it take to make that happen?
If not successful, what was the nature of the failure?
A - total die-off the first winter,
B - gradual die-off over several years, with some production before your tree/bush gave up the ghost, or
C - surviving but not producing optimally.