Why Hardiness Zones, Native Ranges and Ecoregions?

To assure a successful planting, Wild Ones advocates the selection of plants and seeds derived from local or regional sources at sites having the same or similar environmental conditions as the site on which they want to plant.  These environmental conditions are referred to as an ecoregion.  There are many ecoregions maps available, but the USDA Forest Service’s map covering the USA is used in this article.  Why Hardiness Zones, Native Ranges and Ecoregions (pdf)