In some parts of Canada, gardeners may now have the opportunity to cultivate palms and even cold-resistant citrus plants, according to the latest Plant Hardiness Zones map released by the federal government. This update marks the first revision since 2014, assessing the growth potential of various species across the country based on factors such as temperature, precipitation, and weather patterns. The map, established in the 1960s and regularly revised every decade, indicates a shift in plant adaptability to different regions, with some areas now able to support new plant species compared to previous assessments.
The ongoing trend of climate change significantly influences the expanding warmth of Canada with each map update. John Pedlar, a biologist at the Great Lakes Forestry Centre in Sault Ste. Marie, Ontario, underlines the positive aspect of climate change by highlighting the potential for growing new plant species in personal gardens. However, Pedlar emphasizes the need to recognize the broader negative impacts associated with climate change beyond the scope of gardening.
The Plant Hardiness Zones map categorizes Canada into ten zones, ranging from zero to nine, with additional subzones denoted as “A” and “B.” The higher the zone number, the milder the weather conditions, necessitating less hardy plants for survival. The latest map update reveals an expansion of the rare and robust 9A zone, now covering parts of Vancouver Island and the southern regions of British Columbia’s lower mainland. This expansion opens up the possibility of cultivating palms and cold-tolerant citrus plants in these previously unexpected Canadian territories.
Approximately 80% of the country has experienced an increase in its hardiness zones due to rising temperatures. For instance, certain zones in southern Ontario have expanded by at least half a zone. Researchers attribute this shift to a 25% rise in grape cultivation in the region from 1990 to 2020, indicating new horticultural prospects resulting from changes in hardiness zones over time.
Accompanying the plant hardiness zones are species-specific models that offer detailed insights into the performance of individual plants or trees under varying climate change scenarios. These models cater not only to gardeners but also to foresters, ecologists, naturalists, and horticulturalists interested in long-term planting strategies. Dan Richard, the proprietor of Niagara Tropics, a plant nursery in Niagara-on-the-Lake, Ontario, specializing in hardy palm tree varieties, emphasizes the map’s significance in enabling growers to experiment with new plants in their respective regions.
Richard acknowledges the broader implications of the data for industries like agriculture, particularly in adapting to climate change impacts. The updated map aids growers in making sustainable decisions regarding crop placements and greenhouse locations, reducing reliance on artificial climate control methods like gas heating. This shift towards nature-aligned practices enhances the industry’s environmental sustainability.
Rhonda Teitel-Payne, co-coordinator of Toronto Urban Growers, notes the challenges posed by erratic weather patterns on urban agriculture. She highlights the unpredictability and extreme variations in weather conditions, making it challenging for both seasoned and novice growers to plan plantings effectively. Teitel-Payne’s experience with growing a fig tree in Toronto underscores the practical application and significance of the plant hardiness zone map in guiding planting decisions amidst climate change uncertainties.
