The Victoria Day holiday weekend traditionally marks the beginning of the gardening season, and this year, gardeners have access to updated information on the plant varieties that can thrive in their region’s outdoor conditions.
John Pedlar, a research scientist at the Canadian Forest Service, highlighted that the changing climate is a key factor driving the need for updated plant hardiness zone maps. Recently, researchers, including Pedlar, revised Canada’s plant hardiness zone map for the first time in ten years. This tool is essential for nurseries and gardeners to identify plants most likely to survive in specific climates.
The updated map, released by Natural Resources Canada (NRCan) in July last year, incorporates various factors such as rainfall, winter temperatures, and wind patterns. Plant hardiness zones categorize regions with similar climate conditions, ranging from 0A, where few plants grow, to the more temperate 9A.
While significant changes were observed in western Canada, areas like Almonte in eastern Ontario saw a full zone increase, with places like Kemptville and Smiths Falls rising by half a zone. This shift opens up opportunities for gardeners to cultivate cherries, pears, and certain types of apricots that were previously unsuitable for the region. Notably, Ottawa and Kingston maintained their position in Zone 5A.
At Robert Plante Greenhouses in east Ottawa, manager Colin Matassa highlighted the ongoing adjustments necessitated by the evolving climate. Staff are equipped to guide customers on plant suitability for different zones, with clear zone information provided on plant tags. Matassa emphasized the increasing plant variety options available for local planting.
As gardeners explore new possibilities with the updated hardiness zones, the changes also underscore the broader impact of climate change. Nevertheless, it is essential to note that the adjustments to the map are incremental and do not imply drastic shifts in local plant growth patterns.