Foxsflowers, thank you for the article! I like how they mention giving everything a good water in the fall and spring, I find this was the key in how well my plants did or didn't do.

I'm still a zone 3 here, although I think the change in my area subtle, I think it was 3a and it's now 3b. Some of the higher zones plants which are doing well in the microclimates of my yard are geranium 'Rozanne', Russian sage, and oriental lilies.

The thing is that changes in hardiness zones don't always improve growing conditions. I'm in an historic zone 2b, but also in a steep river valley, so have to contend with hotter summer temperatures and, possibly, lower fall minima. Let's say I've moved up to zone 3a, which is plausible, given the fact that our winters have become noticeably warmer, and I can grow all fruit crops that you could around Edmonton.

We used to have fairly steady winter temperatures, because Peace River is pretty far north, but in the past ten years we've increasingly experienced winter thaws that have stripped the insulating snow pack away and left roots exposed to the bitter temps that usually follow. As an example, we didn't have enough snow to have a snowmobile trip in the High Level area in early February, and I have hard time contemplating that!

I now have a problem with winter dieback, which wasn't a problem even ten years ago. I had quite a lot of dieback last year on some of my hardiest 'exotics', like my hackberry, even though the winter was relatively mild, because winter temps were very erratic. My 'tender' exotics, such as Virgilia (cladastris kentuckea) and Devil's Walkingstick (aralia spinosa), did just fine. Even though I've moved 'up' a zone, it's more like I've moved to Calgary, with its erratic winters, than Edmonton with its more stable ones.