Canada's Plant Hardiness Site

Background

Canada´s plant hardiness zones are well known to Canadian gardeners. The original hardiness indices and zones were developed in the early 1960´s through regression models of several climatic paramaters and plant survival data from numerous locations across the country. Since that time Canada´s climate has changed and climate interpolation techniques have improved. We have remapped these zones using data from the original period (1930-1960) and the 1961-1990, 1981-2010, and 1991-2020 periods using thin plate spline interpolation methods. See references below for more details.

Canada´s Plant Hardiness Zones Frontline Express Bullletin No. 13

Getting into the Zone Frontline Technical Note No. 103 (pdf)

Going Beyond the Zones Frontline Technical Note No. 104 (pdf)

References:

McKenney, D.W., Hutchinson, M.F., Kesteven, J.L., Venier, L.A. 2001. Canada´s plant hardiness zones revisited using modern climate interpolation techniques. Can. J. Plant Sci. 81: 129-143.

Ouellet, C.E., and Sherk, L.C. 1967a. Woody ornamental plant zonation I. Indices of winter hardiness. Can. J. Plant Sci. 47: 231-238.

Ouellet, C.E., and Sherk, L.C. 1967b. Woody ornamental plant zonation II. Suitability indices of localities. Can. J. Plant Sci. 47: 339-349.

Ouellet, C.E., and Sherk, L.C. 1967c. Woody ornamental plant zonation III. Suitability map of the probable winter survival of ornamental trees and shrubs. Can. J. Plant Sci. 47: 351-358.

Mckenney, D. W., Pedlar, J. H., Lawrence, K., Papadopol, P., Campbell, K., & Hutchinson, M. F. (2014). Change and evolution in the plant hardiness zones of Canada. BioScience, 64(4), 341-350.

McKenney, D. W., Pia Papadopol, M. H., Campbell, K., & Lawrence, K. (2006). The generation of USDA-equivalent extreme minimum temperature models and a comparison with Canada's plant hardiness zones. Canadian Journal of Plant Science, 86(2), 511-523.

McKenney, D. W., Pedlar, J. H., Lawrence, K., DeBoer, K., & MacDonald, H. (2025). Updated plant hardiness zones for Canada and assessment of change over time. Scientific Reports, 15(1), 22774.