I'm a northern gardener living in what we gardeners call zone 4. I've even learned that parts of my yard are zone 5, or even warmer! Not really uncommon, but my own serendipitous discovery first occurred in the late 90's.
I had placed an order for some perennials from a company that sent you free plants if your purchase met a prescribed minimum amount. While it seems a handy way to purge their overstock, it's not generally an effective strategy when your target audience is from multiple zones.
I wasn't after the free goods, in this case an incredibly gorgeous Peruvian lily meant for zones 7-10. That is very far from my back yard. In fact, isn't that tropical? Well, it would be for this Scandinavian-blooded northerner. When it arrived with my other plants, I planted it on the east side of my home. I figured we might as well enjoy one summer. That delicate-looking lily came back for three summers!
Don't overlook a warmer zone that you may have tucked somewhere on your homestead!