Climatic zones of plant frost resistance. Natural and climatic zones of Russia What does frost resistance mean 4 9 zones

USDA hardiness zones

The specified climatic zoning of territories is an artificial division of places for growing plants, based on the ability of plants to survive in winter conditions. This division is based on a long-term study of winter temperatures.

The assignment of a plant to a particular zone is based on knowledge of the variety's requirements for growth and development conditions. However, even in the same area climatic conditions are not the same. It is well known that it is always warmer on the south side of the house, and in a place protected from the winds (for example, a courtyard or urban development), even the largest "sissies" can grow. Therefore, the given zoning of plant varieties is rather conditional.
With the help of the correct placement of plants (in a warm and calm place), as well as the use of covering materials (spunbond, foliage, spruce branches, hilling, etc.) and “laying” shoots to the ground for the winter, you can increase the climatic zone of your site by 1-2 units. Improvement of the soil regime also helps in this (for example, the introduction of clay on sandy soils, the application of organic fertilizers, the soil being covered with manure, mulching with sawdust, peat, etc.). Then, for example, in the conditions of the third climatic zone, it is possible to grow varieties belonging to the fourth or fifth zone without any problems. In addition, special events such as trunk whitewashing fruit trees in November, shading evergreens with covering material in February or from autumn will help to avoid frost and sunburn in conditions of sudden temperature changes and weather changes.

Table of frost resistance zones:

Zone	From	Before
0
1	-45.6 °C	-53.9 °C
2	-40°C	-45.6 °C
3	-34.4°C	-40°C
4	-28.9 °C	-34.4°C
5	-23.3°C	-28.9 °C
6	-17.8 °C	-23.3°C
7	-12.2°C	-17.8 °C
8	-6.7 °C	-12.2°C
9	-1.1°C	-6.7 °C
10	-1.1°C	+4.4 °C
11	+4.4 °C	+10°C
12	>+10°C

Spring is almost on its heels, the chores of sowing seeds of perennial flowers and annuals begin. Few people know that in the Arkhangelsk region, including in Karelia, the Murmansk region and areas equated to 3-4 climatic zones, there is a very rich list of plants that can be safely grown without shelter, and they will delight us with their flowering. Only some specimens can be capricious, and at first they will need additional shelter or spruce branches, or lutrasil, or sawdust.

I will not list all the plants, but will focus on some of them, which, in my opinion, are not only unpretentious, but also have such qualities as high decorativeness and winter hardiness.
All of the plants listed below can be grown either independently from seeds, or purchased seedlings in specialized stores. Details about some plants can be read at the link on the name of the plant or in the review.
So, alphabetically.

Arabis (rezuha)

Arabis is a perennial ground cover herbaceous plant belonging to the cruciferous family. It grows rapidly with creeping and rooting shoots. The height of the bush is from 15-30 cm. The winter hardiness zone is in the 4th and 3rd zones, it requires shelter for the winter.
It has white and slightly pink flowers. Blooms for 2 years in May-June, sometimes in April.
Arabis loves open sunny places, but can grow well in partial shade, on well-cultivated, loose soils. Unpretentious to watering.
Seeds are sown in March in boxes with light sandy soil, slightly pressed into the soil, without sprinkling with earth. The box is covered with a film or glass, and placed in a lighted place. Shoots appear at a temperature of +20C in 2-3 weeks. Seedlings are planted in open ground at the end of May, at a distance of 20-25 cm. You can sow immediately in open ground in May, as well as aubration. Review of Arabis - "

Astra perennial or small-flowered aster

Has many types color solutions. This is a bush aster with a height, depending on the species, from 30 to 180 cm. The winter hardiness zone of perennial asters is 3/4, does not require shelter for the winter. Good in group and single plantings. Not whimsical to the soil and watering. They grow well in sunny places and light partial shade, in places protected from the wind. There are bush asters that bloom at the beginning of summer (Astra Violetta Alpine), mostly autumn flowering asters, a gift of autumn, which decorates the garden with its flowering, slowly leaving in winter.
Perennial asters can be grown from seeds, sowing them immediately in open ground. If by seedling method, then seeds should be sown on seedlings in March at the beginning of April, the seeds are lightly sprinkled with earth, covered with foil, exposing the box to a sunny place. A week later, the first shoots appear. Plants dive and in mid-late May they are planted in a permanent place in open ground, at a distance of 40-50 cm. At the same time, it should be noted that the seedling height should be at least 10 cm!
You can read more about asters in the articles - and.

Heather is very common in the North-West of Russia. It is an evergreen shrub with strongly branching stems. The flowers are small, the inflorescences are racemose. The height of an adult bush reaches 60 -80 cm. Winter hardiness zone 4, but in zone 3 it requires additional shelter for the winter young plant. Propagated mainly by seeds, division of the bush and cuttings. Light-loving plant. In many sources it is written that the plant is not whimsical to the soil, but this is not so. Heather will not grow on heavy clay soils, therefore, it is preferable to take care of the land where the shrub will be planted before planting, namely, to prepare a mixture of river sand, peat and forest (coniferous) land, or, if heather grows in the forest, then dig up land from its place of growth. It is best to plant heather in May in an open sunny place, protected from the winds. During this period, the bush can easily adapt to the landing site and prepare for winter.
Heather blooms from mid-August to late autumn. Heather should be fertilized with the same fertilizers that are used for azaleas. Top dressing is done every spring at the root.
Heather is a natural antiseptic and immunomodulator, has a diuretic effect.
ABOUT healing properties heather, varieties and planting features articles are written: and

Veronica spikelet

Veronica spikelet (spike) unpretentious plant pertaining to ground cover. Has different color scheme: crimson, pink, white, more often - blue. The length of the inflorescences is up to 10 cm. The height of an adult plant is 20-30 cm. Winter hardiness zone 4. In the first 2 years in zone 3, it requires shelter for the winter. It blooms for a very long time, from early summer to late autumn. It can grow both in the sun and in partial shade. the soil is not demanding.
You can get to know Veronica Koloskova better in an excellent article

Veronica scallop

Very interesting view veronica. Tall, up to 80 cm. It has a two-tone range from lilac-pink to pale blue, sky color. Winter hardiness zone 4. In zone 3, shelter is required for the winter. Best placed in a sunny location. Loves moist soil, responds to watering. Flowering is long.
Veronica is best planted away from home, as she is an excellent honey plant. Has a wonderful aroma.

Heucherella

Geucherella is a hybrid of tiarella and geyhera, belonging to the Saxifrage family, which attracts with unusual leaf color throughout the year. It has high winter hardiness, winter hardiness zone 3.
The maximum height of the plant is 70 cm. It blooms from June to August, throwing out peduncles in the form of panicles. Prefers to grow in shade and partial shade. Grows well. It is not demanding for watering. Since geyherella has superficial roots, by winter it should be mulched with peat or earth. Propagated by division of the rhizome. Combines well in plantings with hostas.
You can read about geyher and geyherella in the article

Another plant that requires attention for its unpretentiousness and beauty. Gypsophila belongs to the Carnation family. Perennial unpretentious winter-hardy plants from 15-20 cm (creeping gypsophila) up to 90 cm in height. Winter hardiness zone - 4. Sowing seeds in breeding beds is carried out in April-May. In autumn, seedlings are transplanted to a permanent place at the rate of 2-3 plants per 1 sq. m. You can sow seeds before winter. Prefers light sandy or loamy well-drained soils. Loves sunny places, tolerates light shading well. Gypsophila does not need special care. Periodically, you need to mulch and add lime to the soil. It usually blooms in June-July, again in autumn. For the winter, the plant is cut and mulched. If the plant freezes in a snowless winter, then Gypsophila reproduces well by self-sowing. You can get acquainted with the types of gypsophila, planting it in the article

Dodecatheon

One of the most mysterious and beautiful, in my opinion, plants. Winters in hardiness zone 3 without shelter. It is unpretentious to the soil, grows well on moist soils in shady and semi-shady places. It has a variety of flower colors from white to bright red, and more recently, yellow. Well complements the shady corners of the garden, looks great with hostas and geyherella.

My dicentra is gaining color, one of 4 varieties I have in my area

Arends' saxifrage

A very unpretentious evergreen, groundcover, forming a dense carpet of small rosettes of leaves. Grows well between rocks. Good as a base on rocky hills. Prefers moist soils and semi-shaded areas, grows well in sunny areas. Plant height up to 20 cm during flowering. Blooms in May-June. The color range of flowers from white to crimson color. Hardiness zone 3. Winters without shelter. Propagated by self-sowing, also by dividing the bush, which has a superficial root system. If propagated by seeds, it is advisable to sow in a separate pot in March, lightly sprinkled with sand. At a soil temperature of +20 shoots appear on the 14-20th day. Seedlings can not dive, planted in open ground in the month of July.

A forest dweller who settled in the shady corners of our gardens. One of the varieties of ferns. The average height is 40-70 cm, some species reach 130 cm. Winter hardiness zone 3-4. Kochedyzhnik is a very unpretentious and cold-resistant plant. Only a few varieties need light shelter for the winter with spruce branches. Most favorable place habitat is a shaded area with fertile, loose and moist soil. Fertilization (from May to July - once every 3 weeks) is only necessary if the land is too poor. The kochedyzhnik does not like direct sunlight, therefore, with excess sunlight quickly loses its decorative effect and stops growing. Also, the plant is adversely affected by sudden changes in temperature and strong wind, which breaks fragile leaves, so it is advisable to plant it in places closed from the wind.
Nomads love moisture, so they respond well to watering and spraying. Requires minimal care. Looks good in group plantings with hostas, dicenters and geyherella.
You can learn more about ferns and their cultivation in the article.

Daylilies (Krasnodrev)

One of the most popular shrub flowers in our gardens. The daylily gained popularity for its unpretentiousness, high frost resistance (3rd winter hardiness zone), and a minimum of care. It looks very good in group plantings with other daylilies. Blooms profusely and for a long time. Capable of re-blooming. The average plant height is 60-90 cm. It grows well in width, therefore, when planting, at least 40-50 cm should be allocated between plants. Plants with bright colors tolerate the sun well, and those with dark ones tolerate partial shade.

Asian lilies and LA hybrids

A wonderful flower with high winter hardiness (most varieties have 3 winter hardiness zones, 4 zones)
Many types, colors. Very hardy flowers. Grow well in sunny areas. Easily tolerate partial shade, shade. Compatible with different colors and plants. Flowering period June-August.
Easily propagated by bulbs from bulbs, which must be planted periodically. The height of the plants is different, there are undersized specimens, there are tall ones. On average, the height of the plant is 60-90 cm. For the winter, lilies should be cut. It can be slightly covered by sprinkling with peat or sawdust. To avoid the loss of bulbs and protect them from rodents, it is advisable to plant lily bulbs in special baskets for planting. I love lilies very much, so I try to update my plantings every year.

In zones 3 and 4 of winter hardiness, cinquefoils and feel very good.
Potentilla grows well in the sun and in partial shade. It does not require shelter for the winter. Very unpretentious to the soil, watering. Herbaceous cultures from 15 to 40 cm in height. Shrub species up to 1 meter in height. Long flowering period until late autumn. Potentilla shrub has healing properties.
The flowers, leaves, shoots of the plant contain a large number of resins, alkaloids, vitamins C, R. Tea is quite popular, which is brewed from this variety of herbs - the drink has choleretic, anti-inflammatory, analgesic, antimicrobial properties. With the help of decoctions, burns, boils, and various wounds are cured. ABOUT shrub cinquefoil can be read in .

Mazus creeping

Creeping mazus is a ground cover plant of the norichnaceae family. Grows in the most different corners the globe. More than 40 types of mazus grow in Central and East Asia and other regions. Mazus is native to the Himalayas. It has been used in Russia since recent times, and has already won the love of gardeners for its unpretentiousness, high winter hardiness (up to -40 with light shelter, winter hardiness zone 4), rapid growth, and is also easy to control. It looks good in the crevices of the paths, in rock gardens.
Mazus is very unpretentious - it grows well in the sun and in the shade, easily tolerates a short drought. Does not tolerate calcareous soils.
Mazus reproduces both by seeds and by dividing the bushes. Seeds can be sown immediately in open ground in spring or early summer. They give excellent shoots, grow quickly and amicably. Shoots also take root perfectly: if you dig out part of a bush and immediately plant it, it will instantly grow.
Creeping mazus blooms with either purple or white flowers profusely and for a long time all summer, until October.

Rejuvenated roofing (Stone rose)

In my opinion, the most unpretentious plant on rocky hills, in rock gardens. Many types of juveniles allow you to create bizarre shapes in flower beds. This plant can really be called a plant for lazy gardeners, which grows on its own and does not require special care. Winters without shelter in hardiness zone 3, possibly even in hardiness zone 2. Well propagated by rosettes.
You can read more about the stone rose in the article.

Bryozoan subulate

Bryozoan subulate is a perennial ground cover plant that forms small, dense, evergreen "pillows" up to 8 cm high. Bryozoan is also called Irish moss. Winter hardiness zone - 4, according to some sources - 3. A common perennial in European countries, in the UK it is often used as a lawn.
The awl-shaped bryozoan forms dense sods both in the light and in the shade, developing well on loamy soils. Gives abundant self-seeding.
In snowless winters, it can freeze slightly, so it is advisable to cover it for the winter.
Seeds of styloid bryozoan are sown in boxes with light soil in May, grown plants are planted in a permanent place in June at a distance of 5 cm from each other. It looks good between the tiles of the paths, on the rocky hills. It is the best imitation of moss thickets in Japanese gardens.

Mylnyanka (Saponaria) basilic-leaved

Perennial ground cover plant, up to 15 cm high. Winter hardiness zone 3.
Soft pads are formed by long, low-creeping shoots. The leaf is narrow, oval. Inflorescences from lilac to pink-red. Sun-loving plant, grows well on open areas tolerates light shade. It is not demanding on the soil, as well as on watering. Careful care is not required. Blooms profusely from June to August. When sown in open ground in May-June, it blooms in the second year.

One of the favorite plants in our gardens, as it is easy to grow and easy to care for. Winter hardiness zone - 3. The most popular types of forget-me-nots are alpine, garden, forest, marsh.
Alpine- grows wild in the mountains of the Caucasus, the Carpathians, the Alps. The leaves have a bluish tint. The flowers are small blue. Blooms profusely. Prefers a sunny location. Winter hardiness is high.
Sadovaya- a derivative of alpine. Propagated by seeds. Blooms 2 years after sowing with abundant flowers. Flowers are often blue, rarely white, pink. The soil is not demanding. Can grow in partial shade. Winter hardiness is high.
Lesnaya- does not differ from the garden.
Bolotnaya- perennial, grown as an annual due to insufficient winter hardiness. It differs from the rest in appearance by larger leaves and light blue large flowers. It has varieties with darker flowers and flowers with double color (blue with a yellow center). Prefers moist soil on the banks of water bodies.

Stonecrop (sedum)

, or - a genus of succulent plants of the Crassula family. The Russian names for stonecrop species are “hernia grass”, “fever grass”. The genus includes over 600 species! There are undersized species, such as Sedum false, a plant up to -25 cm tall, creeping ground cover, like Sedum caustic, or Sedum prominent, Sedum Rural, where the height of the flower reaches up to 50 cm. The color range is from yellow to crimson. They grow very quickly, have high winter hardiness (from winter hardiness zone 3), only some species, for example, Starfish or Angelina sedum from winter hardiness zone 5, in our climate you can grow them as a container home culture.
Sedums grow on any soil in partial shade, in the sun, they are not demanding on watering.
Sedums bloom well and for a long time, almost until the very frosts, sometimes blooming under the snow, like mine

Sedums are propagated by cuttings (stem or leaf), self-seeding. If you bought seeds, then you can sow them either in open ground, or in April-May in boxes, seedlings appear in 2-3 weeks. When 1-2 true leaves appear, it can be transplanted into open ground. Cuttings are carried out from June to September. The cuttings are placed in a greenhouse under glass or on a slightly shaded bed.

sidalcea

Sidalcea is a perennial unpretentious herbaceous plant. The flowers and leaves are similar to a stock rose. Cozy place anywhere, not even in the sun. Winter hardiness zone 4. In zone 3, light shelter for the winter is necessary, having previously cut the plant at a height of 10 cm from the ground. Likes wet soils. Blooms profusely in July-August. Plant height up to 70 cm.

Feverweed

Alpine bluehead is a perennial herbaceous plant. unusual, original, amazing plant. For the first time, the Alpine eryngium was discovered by scientists in the meadows of Switzerland.
Alpine eryngium has 10 varieties. Use it in single plantings, and flower arrangements. Very original cut. The winter hardiness zone of the eryngium is 4. Plant height is from 60 to 100 cm, in some varieties more than 100 cm. It prefers loose soils, sunny areas, does not tolerate excessive moisture. Propagated by seeds and division of the bush. For the winter, the plant should be cut and covered.
You can read more about blueheads in the article.

In our North, yarrow mainly grows wild, ordinary white. But it is so decorative and unpretentious that today there are many color schemes of yarrow that can decorate the garden.
Plant 50-80 cm high. Blooms from July to September.
The plant is unpretentious to the soil, drought-resistant and can grow in shaded areas. In one place it can grow up to 5 years. Propagated by seeds or division of the bush in spring or autumn. When propagated by seeds, it blooms for 2 years. Sowing of seeds is carried out in June-July in open ground, in breeding beds, lightly sprinkled with sand. Shoots appear within 3 weeks, depending on the air temperature. Seedlings are planted in a permanent place in August, maintaining a distance between plants of 25 cm. Winter hardiness zone 3-4. Can winter without shelter.
You can learn more about yarrows in the article

Phlox subulate

A wonderful variety of phlox, which is one of the most unpretentious evergreens.
Phlox subulate has a different color range from pure white to crimson. It grows rapidly into dense cushions, blooms profusely and luxuriantly during May-June. It may also bloom again.
Phlox subulate grows well on poor soils, is not picky about watering. Can grow well in both sunny and shaded areas. IN shady areas Phlox subulate blooms longer than in the sun. It propagates by cuttings, simply by rooting it in a neighboring plot or in a pot, after watering the planting site, and soaking the cutting in Kornevin, and also by dividing the bush. The division of the bush is best done before flowering, so that the delenka has time to take root and bloom this year. Maybe after flowering. Phlox subulate calmly tolerates the division of the bush.
You can get acquainted with styloid phlox in the article

Determining the climate zone is important when choosing plants for a garden. Climate zones – universal system determination of cold resistance of plants.

Climate zones

Quite often when buying planting material garden plants or reading the description of plants in reference books, you can find links to maps of climatic zones. For example, zone 3 or zone 5-6. What are these zones, and what do these numbers mean?

For the first time, the division into climatic zones and their definition was made in the United States by the Agricultural Department. The separation was carried out according to the principle of minimum temperatures in winter period across different regions. It turned out to be very convenient and universal way, with which you can specify the cold hardiness of plants. The system for determining cold resistance using climate zones is very convenient for big countries, like Russia, whose territory captures several climatic zones.

Below is a table with which you can easily determine the climate zone of your region:

The method, of course, is universal, however, gardeners, when buying certain plants, should not forget that in addition to cold resistance, other indicators can also affect plant growth (for example, the level of precipitation in the region or soil type).

In a special issue of our training magazine, only winter-hardy plants that are resistant to our climate. Practical examples of combinations of plants in a flower garden or in a group for shady and sunny places are presented. One of those magazines that you will always have at hand!

01.01.2012

When choosing new plants, pay attention to such a criterion as winter hardiness zones.
Having data about your zone, you will be able to judge with a certain probability whether you can grow a particular plant in the open field.

This system (USDA-zoning) is introduced by the US Department of Agriculture but it is also used in Europe.
Hardiness zones are a certain range of temperatures in which the plant stably overwinters.
The Moscow region is traditionally referred to as the 4th zone.
That is, if zone 4 is indicated on an imported plant, it is assumed that this specimen is able to overwinter in conditions, withstanding frosts down to minus 29 degrees.
However, there are many conventions in this topic.
There is convincing evidence of the successful cultivation of plants in the Moscow region classified both in the 5th and even in the 6th zones. For example, according to many reports, ginkgo winters well in the Moscow region, although it is classified as a 5th zone.
Winter hardiness also largely depends not only on the genetic properties of the plant, but also on its current state. Past illnesses, lack of minerals or too much big harvest weaken the living organism, and its resistance decreases. Plants for which proper care, shows the maximum winter hardiness inherent in this species.
Winter hardiness changes throughout the entire hibernation period of the plant: it reaches its peak by the end of deep dormancy (end of the year in central Russia), and then decreases.
The period of transition from hibernation to the growing season is quite difficult. For example, at the beginning of spring, the bark of trees heats up during the day, and at night it cools sharply, which leads to its damage. Temperature fluctuations also negatively affect the most vulnerable areas of fruit trees - the lower parts of the trunks. Trees can be protected by whitewashing trunks at the end of winter.

Microclimatic factors affecting the winter hardiness of plants.

In addition to temperature, there are many additional factors that affect the development of plants: soil type, daylight hours, wind, humidity. It should be taken into account that the microclimate of areas within the climatic zone may not correspond to the baseline values.
Elevations, southern slopes, large reservoirs have a beneficial effect on plant growth, in contrast to lowlands and northern slopes. In the city, as a rule, the temperature is slightly higher than outside the city.
With careful observance of all the rules of agricultural technology, many trees and shrubs can be grown on the territory of colder zones in protected areas.
The plant may be suitable for five or more zones.
If your hardiness zone is colder than what is recommended for planting the selected plant, special care must be taken in deciding where to plant the seedling on the site.
Dry cold wind puts the development of evergreens at risk, as the process of evaporation from the surface of the leaves becomes more intense, and dehydration occurs. To avoid this problem, it is necessary to plant in places protected from the wind and ensure the correct development of the root system. For this, the soil must be deep, loose, permeable. Mulching works well.
wintering difficulties.
In warm winters with abundant snow cover, plants are threatened with decay - exhaustion in a dark, waterlogged, warm environment, when plants "unscheduled" consume all their nutrients.
Wetting can occur in the lowlands during the period of snow melting or prolonged thaws: melt water is not absorbed into the soil and plants lack oxygen.
The lack of oxygen and mechanical pressures often also occur due to the formation of ice crusts. The formation of an ice crust occurs if, after frequent thaws, very coldy. The crusts are contact (tightly attached) or hanging (practically do not come into contact with plants, they are easy to destroy).
Bulging.
There may be frosts in the absence of snow cover or an autumn drought, or a thaw in which snow water has already been absorbed by the soil. In such conditions, freezing begins at a depth - where there is water. The layer of ice gradually increases and lifts, that is, “bulges out” the upper layers of the soil along with the plants, which leads to the breakage of the roots. Secondary rooting can save the plant from drying out, which can be stimulated with the help of timely rolling of the soil. Crops with roots capable of stretching are resistant to bulging.
Damage from winter drought (at the end of a snowless or little snowy winter with significant solar heating) poses a danger to fruit trees and shrubs in a number of regions of Russia. Under normal conditions, a stable winter cover protects the plant from drying out.

The area in which your garden plot, you can determine yourself - for this you need information about the lowest temperatures in your area over the past 10 years (you can choose a longer time period). Then we calculate the arithmetic mean of all values ​​and see what zone number it corresponds to.
It's obvious that this method cannot be considered absolutely accurate. For example, anomalous temperature jumps can affect the result of calculations. In addition, the same result can be obtained both with a large spread and with minimal fluctuations in values. It is believed that the territories middle lane Russia corresponds to zone No. 5 and those below.
Below are two tables (table 1-short and more detailed table 2) by which the zone can be determined.

Table 1.
Zone Temperature
1 below - 45°C
2 from -45 to -40° С
3 -40 to -34°C
4 from -34 to -29° С
5 from -29 to -23° С
6 from -23 to -17° С
7 from -17 to -12° С
8 from -12 to -7° С
9 -7 to -1°C
10 from -1 to +5° С

Table 2.
Hardiness zone From To
0 a< -53.9°C
b -51.1°C -53.9°C
1a -48.3°C -51.1°C
b -45.6°C -48.3°C
2 a -42.8°C -45.6°C
b -40°C -42.8°C
3 a -37.2°C -40°C
b -34.4°C -37.2°C
4 a -31.7°C -34.4°C
b -28.9°C -31.7°C
5 a -26.1°C -28.9°C
b -23.3°C -26.1°C
6 a -20.6°C -23.3°C
b -17.8°C -20.6°C
7 a -15°C -17.8°C
b -12.2°C -15°C
8 a -9.4°C -12.2°C
b -6.7°C -9.4°C
9 a -3.9°C -6.7°C
b -1.1°C -3.9°C
10 a +1.7°C -1.1°C
b +1.7°C +4.4°C
11 a +4.4°C +7.2°C
b +7.2°C +10°C
12 a +10°C +12.8°C
b > +12.8°C

According to kr.ru

Zoning cultivated plants, is directly related to the definition of the so-called frost resistance zones - climatic regions, to which they can correspond, as acceptable, from the position of laying extensive (industrial) plantations. This concept is more rigorous than the general possibility for the introduction various kinds plants, which allows more extensive experiments in a favorable microclimate.

At the moment, the generally accepted international (American) classification is the USDA zones, containing 11 such gradients with transitional subzones a) and b) (), which, despite its limited flexibility, is still quite often used in our country as a guide.
Most of the territory of the temperate zone (middle zone), with active agricultural activity, fits into the indicators of 3-7 climatic zones of frost resistance. Broad perspective for the introduction of various foreign crops temperate climate starts from the 5th zone, which corresponds to the scale of the average of the absolute minimums: -23.3 °C .. -28.9 °C

There is confusion in understanding these critical indicators for determining frost resistance zones, which are used in agrometeorology in agroclimatic zoning.
The first fundamental calculation parameter is the indicator of the absolute annual minimum, which characterizes the short-term (from several hours or more) setting of cold fronts, which can lead to significant freezing or complete death of the plant. It can be considered only in the context of a limited time frame - either for the period of all currently available observations (often, this is no more than 60-80 years of history), or within the initially set framework: the last climate normal - a period of 30 years of observations, or arbitrarily the taken term - in 20, 40 and more years. To take into account the latest dynamics of climate change, a period of up to 10-20 years is considered. Given the above, an answer in the spirit of “we don’t have -40” is not correct by definition, in the general case, such words do not characterize anything.
More indicative is another calculated parameter - the average of the absolute minimums (as a rule, it is 1.5 times less than the previous indicator). To calculate it, absolute minima are taken for each year, for the required period (as a rule, for the last 10-20 years of observations) and averaged. This parameter and is taken as the unit of account when determining USDA zones.

Consider an example.
Let us take the data of the absolute minimum (Tn indicator) for the State Botanical Garden (GBS) of Moscow (the observation station at the All-Russian Exhibition Center is located a few kilometers from south entrance), as a data source we will use the resource - http://rp5.ru/, look in the sections: Weather archive at the weather station / Weather statistics:
2005 .. -21.5 °C
2006 .. -30.8 °C
2007 .. -23.0 °C
2008 .. -18.3 °C
2009 .. -22.1 °C
2010 .. -25.9 °C
2011 .. -26.4 °C
2012 .. -28.5 °C
2013 .. -18.3 °C
2014 .. -25.4 °C

We get: the average of the absolute minimums over the last 10 years of observations will be (add all the values ​​\u200b\u200band divide by 10): -24 ° C
According to the table of values, we determine for the GBS of Moscow the correspondence to the frost resistance zone 5b, which is typical only for the microclimate conditions of the city (the total frost resistance zone for the Moscow region will already be an order of magnitude lower).

This zone of frost resistance, if we take into account the latest climatic norm - 30 years of observations, passes, approximately, along the border: Minsk - Gomel - Bryansk - Kursk - Belgorod - Voronezh, which is the border, for example, of a possible industrial culture of sweet cherries, but what else insufficient for commercial apricot cultivation (varieties derived from the common apricot genotype), or walnut.
One should always distinguish general recommendations on the introduction (introduction) of certain plant species within the same climatic region - frost resistance zone, and the possibility of a specific microclimate. As a rule, within one generalized zone of frost resistance, one can always find (identify): both more favorable conditions, already transitional, for the next - more favorable neighboring zone, and conditions with burdens, which should be taken adjusted for one zone below. Also, there is not the same thing, the frost resistance of a tree considered as part of a forest biocenosis (forest population) and a separate open personal plot. The forest, in itself, is already the fundamental basis for the formation of the microclimate and other factors that contribute to a more adequate acclimatization of the species.
It should be taken into account that many plants from other regions show an increased sensitivity to environmental conditions that are uncharacteristic for them (humidity regimes, solar radiation, the nature of the change of seasons, etc.), which affects, among other things, the ability to unleash the full potential of inherent genotypic frost resistance. For this reason, often, in foreign nurseries, in relation to such foreign crops, two zones of frost resistance are indicated simultaneously - one for natural growing conditions (within its distribution area), and the second - in the introduction of specific local conditions, which, nominally (by default, ) is set to -1 zone below.

Work on reseeding (reproduction in generations) under new conditions of introduced breeds, as a rule, serves the purpose of normalizing (opening the full potential) of genotypically inherent frost resistance, which is real for many plants. feasible task. But still, this reserve should not be exaggerated unnecessarily. In the general case, it cannot be higher than the frost resistance of a particular species, which manifests itself under natural conditions along the northern border of its distribution, and it is absolutely certain that it can be most fully revealed only in native conditions. So, for example, depending on the place of growth (nature of naturalization), as well as the source of the seed material, in a situation of full passage of all phases of vegetative development, the manifested frost resistance of the Manchurian walnut, which allows it to go through the stage of winter dormancy without significant damage to the aerial part, can vary from - 44 °C to -52 °C and more degrees. At the same time, the ability, let's move on to the example of a walnut, to endure winters with temperatures down to -40 ° C in places of industrial culture (south of Ukraine, for example), and somewhere in the Moscow region, is completely different.
It would be more correct, as recommended by many reference books, when determining frost resistance zones, to take into account another important interconnected indicator - the sum of active temperatures during the growing season (for the temperate zone, they are most often guided by the sum of positive temperatures over +10 ° C), but this is already topic for a separate discussion.

Mar 3, 2014 Alexey