Global warming - is it time to plant southern plants?
Only in February this season we saw a semblance of a real Russian winter with snowfalls and freezing temperatures. Although they were far from typical for our region. Winter 2019-2020 in most of Russia was exceptionally warm. Air temperature rarely dropped below -15 degrees even at night. And many gardeners began to think about whether the “Eurozim” makes it possible to grow heat-loving plants in the middle lane? We will talk about this in this article.
Winter hardiness and frost resistance are not the same thing
In recent years, very warm and little snowy winters are issued more and more often, which makes gardeners think about the possibility of replenishing the assortment with more southern cultures and varieties. Of course, we are not talking about plants in the south of Europe or the tropics, but maybe at least we will begin to grow specimens that winter well, for example, in Poland?
I'm afraid that not everything in this case is as simple as it seems. Plants are very complex living organisms, and their vital activity is not affected by any one factor (for example, temperature), but by their combination. In most of Russia, the climate is continental. It mainly differs from the marine climate of Western Europe in lower average annual temperatures, less rainfall and lower air humidity.
Therefore, even if winter temperatures are more or less suitable, many plants will at least suffer from a lack of moisture. We also recall that winter hardiness and hardiness are not exactly the same thing. Frost resistance is just a component of winter hardiness. The latter includes the ability to withstand stressful factors during the winter, for example, freezing rain, sudden changes from plus to minus and vice versa, prolonged thaws, long periods of severe frost and other troubles.
The generally accepted USDA frost resistance scale tells us the minimum temperatures that a particular plant can tolerate. But for how long it is able to endure them (single frosty nights or for several weeks) and what other factors are necessary for its successful wintering and full growth, we can find out only by studying in detail the climatic conditions of its “native” region and comparing them with ours.
The main problem that heat-loving plants in the middle lane may encounter, even in the presence of regular warm winters, is the instability of the temperature regime. Representatives of the flora of warmer regions are accustomed to the fact that after a mild winter a full spring comes, and after it a hot summer. And when winter temperatures remain high enough, it becomes a signal for active sap flow. Plants are “sure" that spring has finally come into its own, and everything will go according to their usual pattern.
However, nature in our area is extremely unpredictable. And after a long thaw, a real Russian winter may suddenly begin, or severe frosts will return even at the height of the “legitimate” calendar spring. And sometimes late frosts may break out at the very beginning of summer. Plants of local flora are accustomed to such unexpected changes and most often worthily endure all the vicissitudes of the weather. But the southern flora is more vulnerable.
Is warm winter more dangerous than abnormally cold?
Paradoxically, an abnormally cold winter with a lot of snow is less dangerous for thermophilic plants than a warm winter, but after which significant return frosts often occur. So, for example, it happened with a very beautiful decorative willow of Matsudan on our site.
A tree has been growing in our garden for more than 5 years. During this time, quite frosty winters took place. Part of the branches froze, while the others froze the tips, but over the summer the willow was completely restored and added in height. But suddenly, after one warm winter and severe May frosts, a lush three-meter tree completely died. She did not find the strength to give even the slightest root shoot.
Also, many gardeners regularly lose heat-loving plants after the so-called “black winters” (long-term severe frosts without snow), which occur after several warm winters, when the plants seem to have settled on the site and have reached large sizes.
Each plant needs a certain amount of positive (active) temperatures during the growing season. It is, of course, higher in southern plants than in middle-class Aborigines. As you know, the southern regions are characterized by long, hot summers and late onset of autumn. And during this time, the plants manage to accumulate nutrients and prepare for the rest period.
But in the middle lane, summer, at best, can linger until mid-September, after which rainy and significantly cold days come, which is not to the liking of representatives of the heat-loving flora. A long cold spring, which is also not uncommon in our area, is an additional stress factor for southerners. Such plants are not used to making stocks of nutrients that are also designed for long, unfriendly spring.
In addition, warm "unsuitable" often provoke the same "short-lived", which does not reach the climatic norm. A similar relationship was also observed by our ancestors, which was fixed in popular signs: “Fierce winter - sultry summer”, “If it is warm in winter, it is cold in summer”. Modern scientists confirm this state of affairs and give scientific explanations for this.
In simple words, this can be explained as follows: in nature, everything is interconnected, and as you know, nothing disappears and does not arise from nowhere. And while the cold is absent where they should be, "cold reserves" are gathering in the Arctic, and in the future they will certainly "take their own" and fall into our territory. This can happen both in spring and summer. And the lack of active temperatures, as we noted above, negatively affects the endurance of plants.
When will the “ice age” recur?
And finally, there is one more reason not to rely on the thermophilic flora in their gardens. As you can see, many processes in nature are cyclical. And that means that the Eurozim period in our area can also end soon. The NASA satellite data, which record the cyclical fading of the activity of the Sun, speaks in favor of this.
Recall that in the period from 1645 to 1715 there was a period of prolonged cooling, which was called the "Small Ice Age". According to some modern scholars, the new solar cycle, which will begin quite soon - between 2030 and 2040 - will be largely similar to that anomalous cooling of the 17-18th century. Solar activity will decrease by 60% compared to the current one.
By the way, according to the testimonies of those years, during the “small ice age” on the territory of Russia often very cold summers occurred, when frosts could strike already in July-August, and snow appeared in early autumn. At the same time, winters turned out to be so severe that some of them went down in history (the death of two thousand people from the Polish army from the cold, which entered the Russian Empire), pestilence of birds that died literally on the fly from frost.
Of course, such weather anomalies led to constant crop failures and famine. If the scientists' assumptions are confirmed, then, on the contrary, they will have to rely on plants of Siberia, and not on exotic southern wonders.
But let's not panic and warm ourselves ahead of time! Fortunately, here the opinions of scientists, as usual, diverge. According to other sources, our planet is currently undergoing an interglacial period, and no long, significant cooling or icing usually occurs during this period. And the reason for the panic is due to the fact that journalists do not quite correctly understand the scientific article on reducing solar activity and draw incorrect conclusions.
The ice age on Earth, indeed, will take place again, but this will not happen sooner than after several millennia, or even tens of thousands of years. And, of course, this will not be an instant event, as if in a Hollywood movie.
That is, it is quite possible that today's weather anomalies are associated with the preparation of the planet for the Ice Age, which will come in the very distant future. And since this is a very complex process, and the Earth is an interconnected system, today we observe how it is getting colder in one part of the world, while it is noticeably warmer in the other. In particular, abnormal frosts have been observed on the North American continent in recent years, and according to some signs, the Lawrence Glacier is beginning to revive. But in Russia, Mongolia and China it is getting warmer.
And finally, although the threat of global warming is controversial, long-term observations indicate that the average temperature on the planet is rising. And on February 6, 2020, another temperature record was registered in Antarctica.
Dear readers! Summing up, I’ll say that the proverb “where I was born there is useful” is very relevant to plants today. Therefore, in any garden, it is better to give preference to representatives of the local flora. And for the acclimatization of southern plants, there has always existed such a concept as “introduction”, which specialists are engaged in.
In particular, a very encouraging example: the well-known American maple (ash-leaved) in the early 1800s was found unsuitable for cultivation in the middle lane. But already in 1909, this maple began to be massively used in urban landscaping, including in the Urals. And currently, the northernmost point of growth of American maple is the Polar-Alpine Botanical Garden.