A Growing Concern: New Hardiness Zone Map Reflects Warming Climate

The recently updated USDA Plant Hardiness Zone Map is sounding alarm bells for many gardeners. The new zones, released for the first time in a decade, reflect a warming climate that could have profound impacts on gardens across the country.

On average, the 2023 hardiness zones are 2.5 degrees Fahrenheit warmer than the previous 2012 map. This shift is largely attributed to climate change, as average temperatures continue their upward creep. Much of the country – about half – now falls into a warmer zone compared to 2012.

For gardeners, the new map brings some excitement about expanding planting options. Many gardeners are happy to learn they can now grow plants that previously seemed out of reach in their zones. Citrus trees and other delicate fruits may now have a shot of thriving in northern areas where they stood no chance just 10 years ago.

“It’s nice to know I might get a Meyer lemon to fruit before I die,” joked Jonty Brown, an avid gardener in Ohio excited to test the limits of the new zone 6 designation.

However, the implications of the shift are alarming for most gardeners. As growing zones march steadily northward, there are widespread concerns about the impacts of a hotter climate. More heat-tolerant plants may survive, but many garden staples could struggle. And new disease and pest pressure may emerge to threaten landscapes.

“In the back of my mind, we’re like ‘uh, this means things are warming up. So what does this mean in the long run?’” said Missouri gardener Mike Peterson.

The new map provides tangible evidence that climate change is already here – and gardens are on the front lines. Gardeners will be pressed into service as citizen scientists to observe, document, and raise awareness through their plants and backyards. The updated map presents new opportunities, but even more so new challenges to overcome in gardening’s race against a changing climate.