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The deciduous shrub, known as the Japanese rhododendron, belongs to the extensive heather family. It includes about 1300 species, including indoor azalea.
Description of Japanese rhododendron
In the course of long-term selection, about 12 thousand varieties of Japanese rhododendron were bred. Most of the plants reach a height of 2 m. Duration of flowering is 2 months (May and June), while up to 400 flowers bloom on 1 bush. Bushes look very beautiful if there is no foliage or it is just emerging, but the branches are strewn with flowers. Inflorescences of the Japanese rhododendron are formed from 10 or more corollas, most often having an orange-yellow tint. After the corollas wilt, fruits are formed - boxes with very small (less poppy grain) seeds, ripening by October.
The life span of the plant is high, the tallest varieties grow up to 100 years. There are varieties with erect stems and creeping. Mature shoots have a pronounced brown tint, and the most tender young and bare ones are green. The root system is fibrous, without hairs.
In the catalogs of manufacturers of planting material, you can find many varieties and photos of the Japanese rhododendron. The most common shades are orange, yellow, pink and white.
Japanese rhododendron varieties
The classic orange Japanese rhododendron will decorate any area, but the plant looks even more beautiful surrounded by other shades. The following varieties are most popular with gardeners in central Russia.
Japanese salmon rhododendron
This variety has not only a bright shade of lush and large inflorescences serving as a visiting card. Winter hardiness of the Japanese salmon rhododendron is its valuable quality, which made it possible to grow not only in the middle lane, but also in the front gardens of the Moscow region. It is easy to recognize the variety by key features:
- height - up to 2 m;
- flowers - salmon shade, up to 7 cm in diameter, collected in inflorescences of 6-12 pieces;
- flowering duration - 3 weeks from mid or late May;
- foliage of an elongated shape of green color 10-12 cm long by September acquires a fiery hue;
- the bark is gray.
For planting, seedlings are purchased 2-4 years old. The unpretentious Japanese salmon rhododendron is planted where the sun is not all day, otherwise the delicate flowers burn easily. Places near fences are good. The variety is very hygrophilous, but it requires feeding every 2-3 years.
Rhododendron Japanese cream
The creamy shade of the petals in this group of varieties is often combined with the bright yellow heart of the flower and the same large stamens. A pleasant delicate aroma is characteristic of all Japanese rhododendrons. Feature - it does not tolerate the neighborhood with large-sized trees, but it feels great on lawns surrounded by grass, on slopes. It is advantageous to plant it in areas with large elevation differences, therefore it is often used when creating terraced landscape compositions.
Depending on the variety, the height of the bush reaches 1.2-2 m, and grows in one place with proper care for up to 40 years. The leaves grow up to 4-10 cm in length, and the flowers are collected in inflorescences of 6-12 pieces. Corollas are so lush that foliage is almost invisible behind them. By autumn, the foliage on the bushes acquires a yellow-purple color instead of a dark green.
Rhododendron Japanese Babushka
It belongs to the dwarf species. A compact bush in height and width grows only 50 cm. Semi-double carmine-pink flowers are very lush. Only the red Japanese rhododendron looks brighter. Shiny dark green foliage turns yellow by autumn. The variety is semi-evergreen.
It is recommended to plant in semi-dark areas. Refers to the 6th zone of winter hardiness. Loves abundant watering and mulching. Pruning bushes is required once a year - late autumn or early spring before bud break.
Japanese Rhododendron Schneeperle
Azalea Japanese rhododendron Schneeperle belongs to the earliest varieties. Flowering begins in mid-April and lasts until the end of spring. Boiled white flowers look great in festive bouquets, for example, wedding bouquets. Corollas of flowers are relatively small - 4-5 cm in diameter, but very lush, reminiscent of tiny roses.
The bush is unpretentious, but it grows very slowly. The plant, 10 years old, has a height of only 35 cm and a width of 55 cm. The main application is the formation of borders in multi-row decorative plantings. The peculiarity of the variety is that it needs formative pruning at the end of flowering in June. This gives the plant an incentive to form flower buds of the coming season. Withstands frosts down to - 29 ° С. The root system is shallow, prone to expanding in breadth. It is highly discouraged to deepen the root collar, which can lead to the death of the bush.
Rhododendron Japanese Snow White Prince
This variety can also be found on sale under the name White Prince. The flowers are either completely snow-white or with a pale pink core. It looks especially impressive in the vicinity of the orange Japanese rhododendron / azalea. Vigorous bush - up to 2 m in height. Flowers of medium size - 6-8 cm in diameter. Elongated green leaves, up to 10 cm long. Winter hardiness is average, in regions with frosty winters, covering agricultural technology is recommended. Planting material - seedlings of 3 years old. Younger seedlings obtained from seeds are grown in greenhouse conditions. For landing in open ground, choose a shaded place, well protected from strong winds and direct sunlight.
Winter hardiness of Japanese rhododendron
Not all varieties are equally good for regions with frosty winters. Whether a particular variety is suitable for a given area must be clarified in advance. Here is a list of the most winter-hardy varieties that can be grown even without sheltering bushes for the winter:
Name | Winter temperature limit, ° С |
Grandmother | — 23 |
Golden Lights | — 42 |
English Roseum | — 34,4 |
Karens | — 31 |
Mount Saint Helens | — 32 |
Nova Zembla | — 32 |
PJM Elite (PJM Elite) | — 32 |
Rosy Lights | — 42 |
Roseum Elegans | — 32 |
White Lights | — 42 |
In its natural habitat, the Japanese rhododendron grows on mountain slopes at an altitude of up to 2000 m above sea level.
Planting and caring for Japanese rhododendron
It is quite possible, if desired, to grow a beautiful Japanese rhododendron from seeds. This is an interesting case and will take more than one year. The fact is that young plants of the first year of life are extremely demanding to care for, so the sowing is carried out in containers, where the bushes are usually kept for up to 3 years. Only after that they are transferred to flower beds or put up for sale. The older the bush, the higher it is valued. If the average price of a 3-year-old Japanese rhododendron on average ranges from 300 to 1000 rubles, then for a 7-year fair value - from 15 thousand rubles.
Long and slow vegetation is the main reason why varietal Japanese rhododendrons are sold in specialized stores in the form of seedlings of different ages. It is enough to carefully deliver it to the site and drop it off at the chosen place in order to admire its lush spring bloom for many years in the future.The growth of one year is small, undersized varieties can increase by only a few centimeters in height per season.
Selection and preparation of the landing site
The vast majority of Japanese rhododendrons do not tolerate direct sunlight. The bushes are recommended to be planted where the sun appears only for some part of the day - morning or evening. It is optimal to plant bushes along fences or curbs, as well as under the shelter of a facade or other bushes. In a completely open clearing, where the bush cannot hide in the shade for a second, its flowers and leaves will undergo a serious test. The risk of death due to burns is very high.
The soil in the places where the plant comes from is least of all similar to black soil. In fact, this is a complex substrate, in which all kinds of plant residues abound: branches, needles, foliage. For planting bushes, a fertile soil is prepared by mixing it abundantly with mulch and adding clean river sand for additional looseness. On clay and heavy soil, the Japanese rhododendron will wither away. Excellent additives are peat and rotted needles. The acidity of the substrate should be high; Japanese rhododendrons do not like neutral or alkaline soils.
Seedling preparation
Since the planting material comes from nurseries where the bushes were kept in greenhouse conditions, they need to acclimatize before planting in open ground. For this, the tub with the plant is tempered. At first for half an hour, and then gradually increasing the time interval, it is taken out into the fresh air in the warmest part of the day, leaving it in partial shade. After 7-10 days, you can start planting in a previously prepared hole.
Planting rules for Japanese rhododendron
The root system of the bush does not exceed 1 m in height in an adult plant. The planting hole is dug to a depth of 50 cm. Vermiculite or cheaper expanded clay, fine gravel for optimal drainage must be poured onto its bottom.
The removed soil is thoroughly mixed with needles, peat, mulch, a little complex mineral fertilizer is added. A cloudy but warm day is chosen for planting. After placing the roots in the pit, they are covered with a prepared substrate and watered abundantly. A funnel is formed around the trunk of the bush so that when watering the water does not spread by. From above, the ground must be sprinkled with mulch. It is impossible to deepen the root collar; it must be flush with the ground level.
Watering and feeding
The Japanese rhododendron does not tolerate drought well. If the site has a natural or artificial reservoir, then the bushes can be planted along its banks. In other cases, during the entire warm season, the Japanese rhododendron needs regular abundant watering. Mulching the planting with needles or dry foliage will help prevent critical drying out of the soil under the bushes.
Feeding the Japanese rhododendron is almost not required. Once a season, apply a nitri-potassium-phosphorus combined mixture at the rate of 5-10 g / m2... The rest of the plant is obtained from decaying plant residues. Several times over the summer, needles, peat, heather soil are poured under the trunk.
Pruning
The picture shows what a Japanese rhododendron looks like after pruning (2). It is carried out several times. There are types of trims:
- sanitary - in early spring, the broken and frozen branches are removed from the bushes;
- formative - before flowering, get rid of naked shoots without branches, so that a symmetrical neat crown is obtained;
- rejuvenating - after flowering, it is performed to stimulate growth if necessary, it provides for shortening the shoots by 20 cm.
Preparing for winter
Rhododendrons in Japan, growing on gentle mountain slopes, tolerate snowy winters well and do not need any maintenance. In Russia, it is better to take care of the bushes in advance, increasing the chances of the Japanese rhododendron to winter safely.
First of all, pruning is carried out, removing branches affected by diseases and pests. If the bush is old enough, then you can shorten the shoots by 20-30 cm to stimulate the active growth of dormant buds. Winter-hardy varieties do not need shelter, but semi-evergreens will need shelter. For this, agrofibre is used. The covering material has good air permeability, but does not allow the branches of the bushes to freeze out in dry winters with little snow.
Another important activity after the fall of the foliage of the Japanese rhododendron is watering and feeding. Up to 10 liters of water are poured under each bush, dissolving 8 g of superphosphate and 6 g of potassium sulfate in it.
Reproduction
Japanese rhododendron lends itself well to propagation by cuttings, layering, dividing old bushes. On the trunks of winter-hardy varieties, a scion of rare hybrids is made. If you want to get an exact copy of your favorite Japanese rhododendron, you should cut off a stalk at least 15 cm long in the spring. Remove the lower 2-3 leaves. A branch of the Japanese rhododendron is placed in moist soil and is expected to take root for 2-3 months. If by August the root system of the bush has formed of sufficient size, then you can plant it in open ground, otherwise it is postponed until next year. In winter, containers with cuttings are left in a lighted room at a temperature of + 8-12 ° C.
Diseases and pests
With insufficient aeration of the root system, Japanese rhododendrons suffer from numerous fungal diseases. For prevention, it is recommended to regularly treat the bushes with a solution of Bordeaux liquid.
If the soil is not acidic enough, then Japanese rhododendrons can suffer from root rot. This can be corrected only by increasing the acidity of the soil, for example, sprinkling the soil with coniferous litter and peat. Solutions of colloidal sulfur, ammonium nitrate, potassium sulfate also help.
Numerous garden pests common in central Russia affect cultural and wild varieties of Japanese rhododendron. Insecticides have shown good efficiency: "Iskra", "Aktellik", "Fitoverm", "Aktara".
Conclusion
Japanese rhododendron is a very beautiful and non-capricious plant. A correctly chosen planting site, prepared soil and regular watering are the main conditions for active growth and abundant flowering. White, yellow, pink, red inflorescences will be the best decoration for any garden in spring, and lush foliage in summer and autumn.
