In Canada, hardiness zones are used to indicate which plants can survive winter based on climate conditions. The most widely used system comes from Natural Resources Canada, which classifies the country into zones numbered from 0 to 9, sometimes divided into subzones a and b. Below are brief descriptions of each zone, along with examples of native plants from northeastern North America that represent them well.
Zone 0 – Extreme Arctic Climate, the Realm of Cold
In this zone, winter dominates almost entirely. It is the coldest zone in the country. Approximate minimum winter temperatures fall below -45°C.
The climate in this zone is characterized by very long and harsh winters. Icy winds and extended darkness shape a stark landscape where only a few resilient plants from Arctic environments can take root.
Vegetation remains low and creeping to withstand wind and extreme cold.
Arctic willow (Salix arctica): a tiny creeping shrub
Zone 1 – Very Cold North, the Edge of the Tundra
In these cold-swept regions, nature progresses with extreme caution. Winter temperatures remain extremely low, with minimums ranging from -45°C to -40°C. The growing season is short, and only the hardiest species bloom during the brief summer.
Vegetation is typically tundra-like, composed mainly of dwarf shrubs and very hardy perennials.
Dwarf birch (Betula glandulosa): a small northern shrub
River beauty fireweed (Chamerion latifolium): a perennial with bright pink flowers
Zone 2 – Subarctic Climate, Boreal Resilience
Winters in Zone 2 remain severe and very cold, but life persists with determination. Approximate minimum winter temperatures range from -40°C to -35°C.
Hardy perennials and climate-adapted shrubs form a subtle yet resilient landscape.
The first trees appear here, mainly very hardy conifers.
Crowberry (Empetrum nigrum) – a low-growing shrub with berries
Zone 3 – Cold Northern Regions, Hardy Yet Blooming
In this zone, nature begins to express itself more freely. Winters remain harsh, with average minimum temperatures between -35°C and -30°C, but the growing season is slightly longer.
Many deciduous trees, some conifers, numerous perennials, and a few shrubs bring colour during the short yet vibrant summer. This zone supports a wider range of cold-hardy plants.
Black-eyed Susan (Rudbeckia hirta): a hardy perennial or biennial
Zone 4 – Cold Continental Climate, a Northern Balance
Very common across Canada, this zone experiences cold winters (average minimum temperatures from -30°C to -25°C) and relatively warm summers. It represents a balance between sufficiently cold winters and adequately warm summers.
A wide range of hardy perennials, trees, and ornamental shrubs can thrive here. Plants display a rich succession of colours, forms, and textures throughout the seasons.
American Cranberry (Viburnum trilobum): a shrub with white flowers and red berries
Yarrow (Achillea millefolium): a hardy perennial that is very easy to grow
Zone 5 – Cool Temperate Climate, Growing Abundance
In Zone 5, all seasons become milder and plant possibilities expand. Average minimum winter temperatures range from -25°C to -20°C.
Gardens flourish with abundance, combining flowers, shrubs, and even several fruit trees. A wide variety of trees and conifers can thrive here.
Canada goldenrod (Solidago canadensis): a pollinator-friendly perennial that blooms late in the season
Zone 6 – Moderate Temperate Climate, a Thriving Garden
Zone 6 includes specific areas such as parts of the Montreal region in Quebec, southern Ontario, and eastern Nova Scotia. The growing season is longer, and winters are relatively mild. Average minimum winter temperatures range from -20°C to -15°C.
A wide variety of ornamental and edible plants can be grown. The relatively mild climate allows gardeners to explore a broader plant palette, with successive blooms throughout the extended growing season.
Tulip tree (Liriodendron tulipifera): a large native tree with unique flowers
Redbud (Cercis canadensis) – a native shrub with spring blooms
Zone 7 – Mild Climate, a Pacific Influence
This zone is mainly found in certain coastal or urban regions along the Pacific coast. In eastern North America, it is limited to the extreme southern parts of Ontario and Nova Scotia. Winters are relatively mild, with average minimum temperatures between -15°C and -10°C.
It allows for the cultivation of more cold-sensitive species. In these favourable regions, less hardy plants can be grown, giving gardens a distinctive character for Canada.
Red-flowering currant (Ribes sanguineum) – an ornamental shrub native to the West Coast
Zone 8 – Very Mild Climate, Coastal Softness
Zone 8 is not present in eastern Canada, only on the West Coast, particularly in Greater Vancouver, the Fraser Valley, and Vancouver Island (including Victoria). These areas benefit from strong oceanic influence, which moderates temperature extremes and protects against severe cold. Average minimum winter temperatures range from -10°C to -5°C.
Plants typically associated with temperate climates can be grown here. Vegetation may include many evergreen species as well as iconic trees such as the coast redwood (Sequoia sempervirens).
Coast redwood (Sequoia sempervirens) – a giant conifer from the West Coast
Zone 9 – Nearly Maritime Climate, a Garden Without Winter
This is the mildest zone in Canada. It is found mainly in coastal regions of British Columbia. Winters are very mild (between -5°C and 0°C on average), and a wide diversity of plants can survive year-round. However, this zone does not exist consistently in Canada according to official hardiness maps.
Some species typical of Zone 9, though not native to Canada, can be grown with variable success. These include hardy citrus in protected settings, fig trees, and evergreen shrubs.
Common fig (Ficus carica) – a small fruit tree native to the Mediterranean, grown year-round in rare Canadian Zone 9 areas
Conclusion
From the extreme cold of northern regions to the relative mildness of certain coastal areas, each zone sets its limits while offering its own growing opportunities. By considering your hardiness zone as well as site-specific conditions (soil, exposure, drainage), you can significantly improve planting success.
Choosing native plants well adapted to your region helps create landscapes that are more resilient, ecological, and sustainable.
Article written by Audrey Rondeau, Biol., M.Env., Director of Production and Development at Pépinière Vert Forêt, and Suzanne Simard, horticultural writer and horticulture technologist; with editorial support from AI.
Related articles:
- Tree and Shrub Hardiness Zones in Quebec and Canada
- What Is the Best Tree to Plant in Eastern Canada?
- Why Choose Native Plants in Your Landscape Design
References
Plant Hardiness Website of Canada | Natural Resources Canada
