The USDA recently released an updated version of their ‘plant hardiness zone map‘ (or the PHZM if you like using government acronyms). The new map is based on more recent data that spanned a longer time period. In general, most areas moved up 1/2 of a zone, and almost all of the north Texas is now in ‘Zone 8a’, which means the average annual extreme minimum temperature has been between 10 and 15 degrees Fahrenheit.
