Climate change: revision of plants of rusticity of plants in Canada

Opinion to gardeners: The rusticity areas of plants in Canada have just been updated. In addition, to represent the period 1991-2020. However, In Quebec. However, most regions see their rating enhanced by half a zone compared to the previous period (1961-1990), a testimony of global warming.

“The changes are quite systematic and reasonably important. Therefore, That said, gardeners wishing to plant new plants adapted to hot climates will certainly be a little disappointed! In addition, “Points John Pedlar, scientific researcher at the Forestry Center of Great Lakes (Natural Resources Canada) and responsible for revising cards.

Thus, Montreal has been located for a few years in zone 6a. In addition, This means that a shrub like Magnolia can push it. Meanwhile, although it is at the northern limit of its rusticity area. For example, During the period 1961-1990, the Montreal Coast was a lower half climate change: revision plants rusticity zone, at 5b.

Other regions of Quebec have experienced more marked increases. This is the case of certain localities in Témiscamingue, from 2b to 4A in the space of 30 years. “This seems mainly caused by the extension of the growth period,” says Pedlar. The culture of the common pear tree, for example, becomes possible there.

Involved at the Métis gardens since the 1970s. Jean-Yves Roy notes that plants that have not survived in the past can now be cultivated. “Certainly. warmer climates shrubs behave better than before,” says the one who is now a horticultural director of the institution, located in zone 4A.

Seven factors are used by federal government scientists to determine the rusticity clues. including temperatures, precipitation, the duration of the freezing period and the force of the wind. These variables are incorporated into a scale ranging from 0 to 9. The suffixes “A” and “B” designate the half climate change: revision plants rusticity zones.

“In the 1960s. scientists from Agriculture Canada set up gardening tests on 108 sites across the country, where they evaluated the survival of 174 plant species. They then developed a statistical model which establishes a link between the survival capacity of plants. climatic variables, “says Dan McKenney, senior scientist at the Forestry Center of Great Lakes.

The update has just published Messrs Pedlar and McKenney is based on the new climatology. The robustness of a kind of plant towards the weather remains the same from one decade to another.

Climate change: revision plants rusticity

Climate warming

In general, climate change helps southern plants to climb north. However, certain aspects of the upheaval of the climate also harm the adaptation of plants to higher latitudes.

At the Gardens de Métis. for example, we fear mild winters, which, with their thinner snow cover, sometimes bite the sleeping plants badly. “Two years ago, the snow arrived late. climate change: revision plants rusticity Such situations could harm us again in the future, ”explains Mr. Roy.

In vegetable gardens. global warming offers new possibilities, but also disadvantages certain Nordic vegetables, such as turnips, cabbage, lettuce and spinach. “These rustic vegetables in zones 2 and 3 can now have difficulty when it is very hot, in summer,” warns Mr. Roy.

In the long term, Mr. McKenney believes that cards specific to each kind of plant will take over on the rusticity areas. which have a more general vocation. On the Canada Natural Resources website, hundreds of cards are already available.

“Climatic habitat cards [personnalisées pour chaque espèce] Open many doors to help us understand what the future has in store for us. and to think about adaptation issues. The rusticity areas are just a piece of this large puzzle, ”he concludes.

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