The USDA recently updated its USDA Plant Hardiness map for the United States. The 1990 USDA map is the one that I have used for using native plants in natural landscaping and design. (Map credit. Top Map. University of Minnesota)
The new map (on the bottom) shows a warming trend. In the Saint Paul/Minneapolis metro area shows that we went from Zone 4a to Zone 4b. I am not sure what this all means for gardeners and natural landscapers who use native plants. As a landscape designer, I am will continue to create gardens with native plants from Minnesota. There will probably be some attention given to exotic invasive plants and insects and how these plants and insects are adapting to the warmer climate changes.
Using native plants with local genetic sources has always been a good way to ensure that your plants are genetically adapted to your area. It is also helpful to check native plant books and catalogs that may list the hardiness zones of native plants.
