The USDA just released a new plant hardiness zone map. Plant hardiness zones are listed on plant tags to communicate the regions in which plant should survive without extra winter protection.
You know how those moisture-retaining gels swell when placed in water? That's what I envision happens to brains of new gardeners as they soak up any and all available how-to gardening information – I was a novice gardener once long, long ago and did just that. It's important to seek learned, sound advise from gardening friends, trusted nursery staff, local agriculture extension departments, books, blogs, websites, and magazines. Unfortunately not all gardening information is as clear as it should be.