Warmer Temperatures Lead to Shifts in Hardiness Zones
A new release of the USDA’s Plant Hardiness Zone Map confirms that Earth’s temperatures are warming, a reality that could present more challenges than opportunities in the future.
*2023 USDA Plant Hardiness Zone Map. The map comprises thirteen zones across the U.S., each representing a difference of ten degrees Fahrenheit. The map further divides the zones into half-zones designated as “A” and “B,” with a five-degree difference between them.
Warmer Average Temps Impact Plant Hardiness Zones
Half of the country has shifted to warmer zones, according to a new map released by the U.S. Department of Agriculture (USDA) late last year, the first significant update since 2012. The new map used 30-year averages of the lowest annual winter temperatures at specific points across the country to determine current plant hardiness zones, showing a temperature shift ranging from 0-5 degrees Fahrenheit.
What does this mean for our landscapes?
While the warmer grow-zones may provide new possibilities for plantings, it also brings risks, including:
- Some insects that typically die off in the winter months could survive year-round, making heat and drought-stressed plants their target in the summer months.
- Since fruit trees often require a series of cold days each winter to properly flower for optimal spring fruit-bearing, warmer temperatures could negatively impact the overall harvest.
- An increase in the spread of invasive plants, threatening native plants and animal life, and ultimately reducing nature’s biodiversity.
Should this affect our plant care right now?
While there may be future risks, for now there is no need to change the plants in your garden, according to the USDA. The Department states, “What has thrived in your yard will most likely continue to thrive.”
Call your arborist if you have any questions about the impact of warmer temperatures on your hardiness zone.
