We get asked that a lot, and many people often use the word “hardy” to describe a plant being tough, hard to kill, adaptable, easy to grow, or brown-thumb-friendly. But did you know HARDINESS actually refers to a plant’s ability to withstand the cold? That’s why you can go to Florida and see street plantings of trees we use as houseplants or patio plants in our area – they are hardy in Florida but are not hardy in our hardiness zone.
The USDA recently released a new Plant Hardiness Zone Map, the first revision in 22 years. The map seen here breaks areas into bands of 5° temperatureranges based on the average annual extreme minimum temperature, derived from
sophisticated tracking methods and weather models. But in layman’s terms, you can type in your zip code and it will tell you your official zone! (And when you are drooling over something exotic in Southern Living, it may help you decide whether to build your whole garden around it, or enjoy it for a season in a decorative pot
on the patio!)
Interestingly many of the zones are coming out to be 5° warmer than on the old map, but this is thought to be more a result of how the studies were done, the 30-year study period, and increased number of weather stations, rather than a case for global warming. (And in some mountainous regions the zones actually came out cooler!)