On November 15, the USDA released an updated Plant Hardiness Zone Map (https://planthardiness.ars.usda.gov/). The new map reflects data from significantly more weather stations, a sophisticated algorithm, and new tools designed to be interactive and internet-based. Users can now search by zip code for Plant Hardiness Zones detailed within a half-mile radius. New data reflects microclimates like urban heat islands and cold mountain tops.
For Kansas, most of the state shifted about a half zone warmer. We still have pockets of Zone 5 in the north, but the range of Zone 7 in the southern part of Kansas is more extensive. As industry professionals, we should continue to focus on recommending plants that can handle Zone 5 plant hardiness because we will continue to experience extreme weather events. However, many of the more southern communities in Kansas can also expand their plant palette with species originating in slightly warmer climates–horticulture is always an adventure with new-to-us species and cultivars. These zone changes may also reflect longer season extension for some food crops.
The USDA Risk Management Agency uses the USDA Plant Hardiness Zone Map to set crop insurance standards. Other scientists use the data in models that might indicate the spread of weeds, insects, or diseases.
It’s important to note that these warmer plant hardiness zones do not indicate global climate change. Data used for this map is extensive, about 30 years worth at over 13,000 weather stations, but it is not the required 50 to 100 years of data that will provide reliable evidence of global climate change. It simply reflects greater available detail, tools, and methods.
More information can be found at the USDA Press Release and Map Creation web pages.
We will work on reviewing and updating our plant recommendation publications for Kansas. Let us know if you have questions or thoughts–please reach out!
