Stumbled across this story the other day at a website called The Daily Climate.
This should make you folks up north feel better because, apparently, the hardiness zones are shifting in your direction. In other words your zones are becoming “warmer” and may change your planting choices.
I won’t go into a full discussion here because The Daily Climate post is so detailed and informative.
Here’s the direct link to the USDA map which links to more in-depth information about each hardiness zone.
I haven’t studied it in detail for down here in the high desert of southern New Mexico, but maybe someday I’ll be able to plant more tropical plants? Some like the Red Bird of Paradise already overwinter at the lower elevations, but here up in the foothills of the Organs it depends a lot on the micro-climate in each location.