Weather Changes Mean A New Map

摘要

FOR years, people have been talking about changes in weather; particularly how our winters seem to be getting shorter and colder for shorter periods of time. Of my friends in Montreal, I don't know anyone who prepares an outdoor skating rink in the backyard as we did every year growing up. Even with last year's snowy winter, winters are simply not as cold as they were when I was a kid. As greenhouse folks, this may be a good energy-saving thing, but winter temperatures are the basis for the highly popular USDA Plant Hardiness Zone Map. This map is used by everyone planting perennials, shrubs and trees. It is as well known by gardeners as it is by professionals, used in every catalog, heard in every talk and the subject of endless conjecture. The map consists of 11 hardiness zones, based on minimum winter temperatures, and everyone knows his or her USDA hardiness zone.