The U.S. Department of Agriculture on Thursday issued its new plant hardiness map for farmers and gardeners, and it reflects a warming climate.
Growers rely on the map, which delineates different plant hardiness zones based on average minimum temperatures over a 30-year period. It had not been updated for 11 years.
State horticulturist Gary Fish says the map confirms the warming trends that growers have observed, and will allow some plants to thrive in new areas.
"There's a lot of things that you can grow in some parts of Maine, like peaches and cherries and even paw paws, and those will be more easily grown and not winter-killed as often further inland in Maine," he says.
But Fish says the warmer temperatures are also allowing invasive species, such as the hemlock wooly adelgid, to expand their ranges.
And Caleb Goosen, of Maine Organic Farmers and Gardeners Association, advises growers not to be complacent about the new zones, because increasingly variable winter conditions can damage plants at the northern margin of their ranges.
