As gardeners in a northern climate, we’re quite aware of the challenges of growing plants that may be borderline hardy in the region where we live. “Will it grow in my zone?” is the pertinent question about winter hardiness for perennial plants. Scientists have developed maps of plant hardiness zones for Canada based on seven climate variables (not only the average annual … [Read more...] about Plant hardiness zones changing, slowly
plant hardiness
Hardiness zones are drifting
The United States Department of Agriculture has updated its 1990 plant hardiness map, and it reveals that hardiness zones are drifting. The new USDA map reflects average cold temperatures from 1976 through 2005, and illustrates the warming trend we’ve noticed in recent winter seasons. The new data indicates an average 5°F temperature increase, making a half zone movement … [Read more...] about Hardiness zones are drifting
Global warming and plant hardiness
I’m confused. Current winter weather predictions (2010-11) from Environment Canada, the Weather Network and the Farmers’ Almanac all agree that my southern Ontario garden will have normal temperatures and normal snowfall this winter. But does anyone know what normal is anymore? Over the past decade winters have grown gradually warmer with less snow, and 2010 was the warmest … [Read more...] about Global warming and plant hardiness
