At long last there is a new USDA plant hardiness zone map.
This guide was last updated in 1990 and was long overdue for a revamping to take into account climatic changes. These planting maps are based primarily upon average minimum temperatures. There are a total of 13 zones. 1 is coldest (-60 to -50). 13 is hottest (60 to 70) and is found only on Hawaii and Puerto Rico.
The new map can be found on the USDA website. It uses 30 years of weather data gathered from 1976 to 2005. It is more precise than the 1990 version, showing It is designed for the Web and using their zip codes you see your zone down to half-mile segments. Many areas now find themselves in warmer zones
Cheyenne is now in a new climate zone.
Cheyenne used to be solidly in zone 4 is now one full zone warmer, zone 5.
“Because this map is mostly based upon temperature, it doesn’t account for Cheyenne’s extreme winds and lack of winter snow cover. Therefore, I would caution people to not jump blindly into growing zone 5 plants and instead look at what is proven to do well here,” said Cheyenne Botanic Gardens Director Shane Smith. Cheyenne gardeners should instead stick to following the colder, zone 4 designation especially when selecting trees and shrubs, stated Smith.