According to Guinness World Records, the most cold-hardy tree in the world is found right here in our region.
| “Larches (genus Larix) are the most cold-hardy trees. Among them, tamarack (Larix laricina), native to northern North America—primarily Canada—can survive temperatures as low as -65 °C (-85 °F) and is typically found near the northern tree line, at the edge of the tundra.” — Guinness |
But how does tamarack survive such extreme cold?
In this article, we explore how the most resilient trees withstand winter in Eastern. Alongside the Tamarack (Larix laricina), we highlight several cold-hardy species from northern ecosystems. Because winter stress is multifaceted, we also look at tolerance to road salt.
What Challenges Do Trees Face in Winter?
Winter Desiccation
Cold, dry winds can cause dehydration. In winter, trees cannot absorb water from frozen soil, while wind and road salt increase water loss—especially in conifers.
During freeze-thaw cycles, water may temporarily thaw and evaporate but cannot be replaced. This leads to winter desiccation, which can damage exposed tissues.
Extreme Cold and Freezing
Very low temperatures can damage trees, especially those planted at the limit of their hardiness zone. Rapid temperature drops may also cause frost cracks, particularly in young trees.
Road Salt
Road salt can damage both conifers and deciduous trees. In conifers, it causes needle burn and dehydration. In deciduous trees, it can damage buds and affect overall structure.
For practical protection strategies, see this article on winter protection.
How Do Trees and Shrubs Resist Freezing?
Trees in northern climates rely on a combination of physiological adaptations to survive winter.
Cold Acclimation
In fall, decreasing temperatures and shorter days trigger cold acclimation, allowing trees to prepare for winter.
Bud Formation and Dormancy
By late summer, trees form buds for the following year. These buds are protected by scales that reduce water loss and shield them from rapid temperature changes.
As temperatures drop, growth slows, shoot maturation (lignification) occurs, and trees enter dormancy.
Hardening
During hardening, sugar concentration increases in cells, lowering the freezing point of fluids and limiting ice formation.
Cell membranes also adapt to remain flexible in cold conditions, ensuring proper function.
Water Management in Cells
Trees also survive freezing by controlling how water behaves inside their tissues.
Supercooling
Water can remain liquid below 0 °C, preventing ice crystal formation inside cells.
Extracellular Freezing
Water moves outside cells, where ice forms safely, avoiding cellular damage.
The Most Cold-Hardy Trees and Shrubs in Eastern Canada
Hardiness zones provide a useful indication of cold tolerance. Species with lower zone ratings are generally more resistant to extreme cold.
However, factors such as plant health, site conditions, and proper acclimation also influence survival.
Most Cold-Hardy Trees
Tamarack (Larix laricina) (Zone 1a)
The most cold-hardy tree. It thrives in peatlands and poorly drained soils. It is also valued in landscaping for its form and golden fall colour.
It is one of the few deciduous conifers, shedding its needles each fall.
White Spruce (Picea glauca) (Zone 1a)
A highly resilient conifer that grows up to the northern tree line.
Quaking Aspen (Populus tremuloides) (Zone 1b)
A fast-growing pioneer species that colonizes disturbed sites and supports wildlife.
Most Cold-Hardy Shrubs
Labrador Tea (Rhododendron groenlandicum) (Zone 1a)
An evergreen shrub adapted to acidic soils, commonly found across northern Canada.
Highbush Cranberry (Viburnum trilobum) (Zone 2a)
A hardy shrub that tolerates cold, poor soils, and partial shade. Its fruit is edible and rich in vitamin C.
Symptoms of Frost Damage
Common signs include:
- Buds that fail to break in spring;
- Weak or stunted leaves after bud break;
- Needle or leaf browning (winter burn);
- Bark damage or frost cracks.
Are Road Salts Harmful to Trees and Shrubs?
Yes—road salt can significantly impact nearby vegetation. It is often spread beyond roads by snowblowers and traffic.
Conifers are particularly sensitive, as salt causes dehydration and needle damage. Deciduous trees may experience bud injury and structural issues.
More Salt-Tolerant Deciduous Trees
- Honey Locust (Gleditsia triacanthos)
- Norway Maple (Acer platanoides)
- Russian Olive (Elaeagnus angustifolia)
- Japanese Tree Lilac (Syringa reticulata)
More Salt-Tolerant Conifers
Article co-written by Audrey Rondeau and Suzanne Simard.
References
Bouchard, Julie. De-icing salt. Accessed November 3 2024, at the following address: http://arbres.ccdmd.qc.ca/fiche/sel-de-deverglacage
Desjourdy, A. (2014). Recommended urban trees. Association québécoise des Producteurs en Pépinière. https://aqpp.org/realisations/publications/repertoire-des-arbres-recommandes-en-milieu-urbain
Hydro-Québec. (2010) Trees and shrubs guide (4th edition). Hydro-Québec Distribution.
Lavallée, A. Winter desiccation and frost damage. Centre de foresterie des Laurentides. https://ostr-backend-prod.azurewebsites.net/server/api/core/bitstreams/e4f1d9f0-ed70-443f-bd0a-769a0626d2a1/content
Most cold-tolerant trees. (n. d.). Guinness World Records. Accessed on November 1, 2024, à l’adresse https://www.guinnessworldrecords.com/world-records/87209-most-cold-tolerant-trees.html
Ontario.ca – The effects of winter on tree fruit. Accessed on November 1, 2024, at the floowing address: https://www.ontario.ca/page/effects-winter-tree-fruit
Ontario.ca | Common disorders on broad-leaved trees. Accessed on Novembre 6, 2024, At the following address: https://www.ontario.ca/page/common-disorders-broad-leaved-trees
