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Rhododendrons are a rather extensive genus of ornamental shrubs and semi-shrubs, including more than 600 species. Due to the unpretentiousness of cultivation and excellent appearance, these plants are widely used to create flower arrangements, as decoration of parks and squares, in ornamental gardening. Of particular interest to flower growers is the evergreen rhododendron. It fully combines all the decorative qualities of this plant, and resistance to negative temperatures makes it possible to grow it in many regions of the country.
Description of evergreen rhododendrons
Evergreen rhododendrons belong to the Heather family. To many gardeners, this shrub may be known as the azalea, but this is not entirely correct. Azaleas are a separate subspecies of rhododendrons, and among them there are also many evergreens.
A complete description of evergreen rhododendrons is given in the table:
Parameter | Value |
Type of plant | evergreen perennial shrub |
Root system | Superficial |
Stem | Straight, height from 0,5 to 4 m, depending on the variety |
Leaves | Dark green, glossy, oval-lanceolate, with a dense leathery surface |
Flowers | They are shaped like bells. Collected in cap-shaped inflorescences of 6-20 pcs. Colors can be very different: white, pink, purple, yellow, etc. |
Flowering period | May June |
seed | Collected in seedlings – boxes. Ripen in late August or early September |
Varieties of evergreen rhododendrons
Of the many species of rhododendrons, only a small part is deciduous shrubs. The rest of the foliage is not shed for the winter, but only rolled into a tube. Below are the most famous varieties of evergreen rhododendrons.
Katevbinsky. It is one of the most popular types. One of the tallest rhododendrons, reaching a height of 4 m. With good care, it can live up to 100 years.
Blooms in May-June. Pale purple flowers are collected in large inflorescences of 10-20 pcs. The bush is dense, the diameter of the crown can reach 2 m. On the basis of this variety, a large number of frost-resistant hybrids of various colors have been bred.
English Roseum. One of the well-known hybrids obtained on the basis of Katevbinsky rhododendron. It grows in a dense bush, the height and crown diameter of which can reach 2,5 m. The flowers have a characteristic mauve color with orange speckles. Dome-shaped inflorescences usually contain 8-10 flowers. Below in the photo is a hybrid evergreen rhododendron English Roseum.
The grade differs in good resistance to adverse weather conditions, well transfers frosts, rains and a drought. Blooms in May-June.
Karens . The plant belongs to the Japanese azaleas. Forms a dense compact bush with a diameter and a height of up to 1,5 m. The flowers are reddish-lilac, with dark specks.
A distinctive feature of the variety is a strong aroma of flowers. Azalea Japanese Karens blooms in May-June.
New Zembla. Another hybrid of Katevbinsky rhododendron. Bushes differ in solid sizes – up to 2,5 m in height and up to 2,1 m in diameter. The flowers are reddish-pink, bright, with dark burgundy spots. Collected in dense spherical inflorescences, from a distance resembling peony flowers.
The evergreen rhododendron Nova Zembla blooms in May. The plant tolerates drought and direct sunlight well.
Marcel Menard. The bush grows up to 1,5 m. The crown is dense, up to 1,2 m in diameter. It blooms with large (up to 9 cm) purple flowers in the shape of a wide bell with a characteristic golden middle. In a cap-shaped inflorescence there can be from 9 to 18 flowers.
Flowering begins in May, sometimes the evergreen rhododendron Marseille Menard blooms again in September.
Erato. Bush up to 1,5 m high with a wide spreading crown. The flowers are large, bright red, lighter on the periphery, with an uneven edge. Evergreen rhododendron Erato – pictured below.
Blooms in May-June. The variety has good winter hardiness and can withstand temperatures down to -27 ° C.
Alfred. A low-growing variety of evergreen rhododendron, growing only up to 1-1,2 m. Flowers are medium in size, 5-6 cm, pale purple with golden freckles. Collected in hats of 15-20 pcs.
The winter hardiness of the variety is good, up to -25 ° С.
Lita. A rather tall dense bush that can grow up to 2,5 m. The flowers are large, with an uneven wavy edge, up to 7 cm in diameter, collected in dense inflorescences of 10-15 pcs. The color is pink with a purple tint, on the upper petal there is a blurry speck of golden-olive color. The pink evergreen rhododendron Lita is shown in the photo below.
The variety has excellent frost resistance – up to -35 ° C.
Humboldt. Hybrid of the Katevbinsky rhododendron. A dense compact bush up to 1,5-2 m high. The flowers are purple-pink, light, collected in dense cap-shaped inflorescences of 15-20 pcs.
The flowers have a characteristic spot of red-brown color. Winter hardiness – up to – 26 ° С.
Pohyolas Doter (Pojola Doter). One of the most winter-hardy varieties of evergreen rhododendrons. Hybrid variety of Finnish selection. The bush grows up to about 1 m. The crown is quite dense, wide. The flowers are light purple, almost white, with a reddish corrugated edge. Collected in inflorescences of 8-12 pcs.
The evergreen rhododendron Pohyolas Doter has excellent frost resistance, it can withstand temperatures down to -35 ° C.
Helliki – Another hybrid variety of evergreen rhododendrons of Finnish selection. It is a low compact shrub up to 1-1,2 m high. The flowers are bright, juicy, crimson-pink, with orange splashes. Collected in inflorescences of 8-12 pcs.
Helliki evergreen rhododendrons have several sub-cultivars that differ in color: Red, Helsinki University (pink), The Hague (purple-pink). All of them are distinguished by excellent winter hardiness – up to -34 ° C.
Planting and caring for evergreen rhododendrons
In the wild, rhododendrons grow mainly in regions with a subtropical and temperate climate. Some species of this shrub are also found on the territory of Our Country, for example, in the south of Siberia and the Caucasus. To successfully grow evergreen rhododendrons in other climatic conditions, they will require some care.
Selection and preparation of the landing site
Evergreen rhododendrons do not like bright light, this can cause foliage burns. Therefore, for their landing, it is better to choose a place where the sunlight will be diffused. The site must be well protected from the cold wind. The groundwater level should not be higher than 1 m. Evergreen rhododendrons get along well with almost all plants, but it is better to plant them next to those whose roots go to a deeper level. These are pine, larch, oak, apple tree. But with shallow-rooted linden, maple or chestnut, rhododendrons may have competition.
Seedling preparation
Evergreen rhododendron seedlings can be purchased at specialized stores or nurseries. They are sold, as a rule, in special containers filled with soil substrate. When choosing a seedling, you should pay attention to its appearance. It should look healthy and have no signs of disease (yellowing of leaves, white bloom, etc.).
Rules for planting evergreen rhododendrons
Evergreen rhododendrons can be planted in spring and autumn. In spring, planting can be started after the snow has completely melted and the soil warms up to + 8-10 ° С. In different regions, this time may fall on April-May. Autumn transplantation can be done in September-November. The evergreen rhododendron tolerates transplanting well, so you can plant it and replant it at another time if it does not bloom at the same time.
The size of the planting hole should be twice as large as the volume of the root system of the seedling. At the bottom it is necessary to pour a layer of drainage. To do this, you can use fragments of bricks, expanded clay, large gravel. Ordinary land for evergreen rhododendron is not suitable, therefore, for planting, it is necessary to prepare a sufficient amount of soil substrate in advance. It must have a pronounced acid reaction, therefore, it must include high-moor peat and coniferous litter in its composition.
On the day of planting, the container with the seedling is abundantly spilled with water. This will greatly facilitate the extraction of the plant. The seedling, together with a clod of earth on the roots, is placed in a planting hole strictly vertically and covered with a soil substrate, periodically compacting it. In this case, the root neck of the plant should be on the same level with the surface of the earth. After the pit is completely filled, the seedling is abundantly spilled with water, and the root zone is mulched with peat or fallen needles.
Informative video about planting and caring for rhododendrons:
Watering and top dressing
Evergreen rhododendrons love moderately moist soil, however, excessive watering can lead to water stagnation in the roots and their decay. The state of the leaves can serve as a guide. If they begin to lose their natural luster, then the plant needs watering. Evergreen rhododendrons should be watered with rain or settled softened water. A day before watering, you can add a little peat to the container. This will further soften the water and slightly acidify it.
Evergreen rhododendrons need to be fed throughout the season. It is better to do this in small portions, but often. It is best to use mullein infusion diluted in water for feeding. Until mid-summer, plants can be fed with nitrogen-containing mineral fertilizers, for example, ammonium sulphate. Then nitrogen application should be stopped. Further top dressing is carried out only with potash and phosphorus complex fertilizers, so as not to stimulate excessive growth of green mass.
Trimming
The rhododendron bush is quite dense and compact, so it is usually not formed. Pruning can only be carried out for sanitary purposes in order to clean the plant from broken or dried branches, as well as shoots that are diseased or damaged by pests. Periodically, bushes need to be rejuvenated by cutting out perennial shoots and growing younger stems instead. Such pruning of evergreen rhododendrons is carried out in the spring, before flowering, along with other care work. At the same time, no more than ¼ of the bush is removed. Large sections must be covered with garden pitch.
Some gardeners remove faded flowers by cutting them off immediately after flowering. Such a measure helps the plant redistribute nutrients and direct them not to the laying and ripening of seeds, but to the formation of new flower buds. The following year, the flowering of such bushes will be more abundant.
How to prepare an evergreen rhododendron for winter
Preparing for winter is an obligatory part of caring for evergreen rhododendrons in autumn. In winter, plants can suffer not only from low temperatures, but also from the severity of adhering snow, cold wind. To prevent this, a fence is installed around the bush – a house. Its frame can be made of wire or wooden slats. With the onset of cold weather, the shoots are tied into one bundle and tied to a support. Covering material, such as burlap, is stretched over the fence. Low-growing varieties with flexible stems can be bent to the ground and fixed. Despite the frost resistance of many varieties of evergreen rhododendrons, such additional measures for the preservation of the bush in the winter will be quite useful.
The roots of evergreen rhododendrons are located close to the surface, so the root zone must be insulated before wintering. This can be done with the help of peat, pouring it with a layer of 15-25 cm.
Why do the leaves of the evergreen rhododendron turn red
Reddening of rhododendron leaves is a completely natural process. There may be several reasons for this phenomenon.
- Age. Often, redness or yellowing of the leaves of the evergreen rhododendron is associated with a natural change of leaves. Leaves live 3-4 years, their redness is a signal that they are gradually dying off.
- Cold. With the onset of the cold season, some types of rhododendrons change color.
- Wrong fit. Reddening of the leaves of the evergreen rhododendron after a short time after planting or transplanting indicates unsuitable conditions for its growth. This may be direct sunlight, lack of moisture, etc.
- Phosphorus deficiency. Despite frequent feeding, the plant may feel a lack of this element. Phosphorus deficiency can be quickly replenished by spraying the bushes with a solution of potassium monophosphate. This substance is well absorbed by all parts of the plant, but quickly decomposes, so this top dressing is done several times per season.
The reason for the change in the color of the leaves of evergreen rhododendron can be various diseases, but in this case, the color of the leaves often becomes yellow or brown.
Reproduction
Evergreen rhododendrons can be propagated by seeds or vegetative propagation methods:
- cuttings;
- layering;
- division of the bush.
Seeds can be planted in November or from January to March. Sowing is carried out in special containers filled with a mixture of peat, sand, and soil taken from under coniferous trees. Germination of rhododendron seeds is good. The substrate must be periodically moistened with acidified softened water, and the growing seedlings should be illuminated with phytolamps, providing them with a 12-hour daylight hours. Plants are kept in containers for up to 3 years, taking them out into the open air only in the summer. Only then the seedlings are planted in open ground for growing.
The seed propagation method is the longest and most laborious, since the seedlings need constant care for a long time. Seedlings can begin to bloom only after 6-10 years.
Vegetative methods of propagation of rhododendrons are more transient. In late spring or early summer, you can propagate by cuttings. To do this, use semi-lignified stems of the plant, cutting them into pieces 12-15 cm long. The lower part is soaked for a day in a growth stimulator, after which the cuttings are planted in containers filled with a substrate – a mixture of sand, acid peat and coniferous earth. This soil mixture is best purchased at a specialized store. Planting cuttings produced at an angle of 30 °. After that, the substrate is moistened, and the container is covered with a film and cleaned in a warm place.
Evergreen rhododendrons take root for quite a long time, from 4 to 5 months. All this time it is necessary to maintain the optimum temperature (+ 25-30 ° C), as well as high humidity. You can speed up the process with the help of additional illumination of the cuttings with phytolamps, increasing the daylight hours to 15-16 hours. As they grow, the seedlings are carefully transferred to larger containers, trying not to disturb the clod of earth on the roots. The rhododendron is grown for 1-2 years, after which it can be planted in a permanent place.
Getting layering from the mother bush of evergreen rhododendron is quite simple. To do this, you can use 2 methods:
- Bend several side shoots to the ground, fix with a bracket and cover with a mixture of sand and peat. In this case, the underground part of the stem is split lengthwise, and a chip or branch is inserted into the split. This technique provides faster and more active rooting. Regular watering ensures that the cuttings have a rapid growth of their own root system. In autumn, the layering is not cut off so as not to weaken before wintering; it hibernates together with the mother bush. Transplantation is done in the spring.
- Cover the base of the bush with plenty of soil substrate. In this case, part of the side stems, with sufficient watering, will take root on their own. In the spring, they can be carefully cut off from the mother bush and transplanted to a new place for growing.
Dividing a bush is a fairly simple way to propagate rhododendrons. In this case, an adult, overgrown bush is divided into several parts, divisions, each of which has its own stems and root system.
Diseases and pests
Evergreen rhododendrons get sick quite often. The reason for this may be violations in care, weather factors, poor-quality planting material. Fungal diseases are the most dangerous for these plants. These include:
- Rust.
- Phytophthora.
- Spotting.
- Gray rot.
You can recognize diseases by changing the color of the leaves, the appearance of putrefactive deposits, white or brown plaque, modifying the shape of the shoots or leaf plates.
In some cases, plants can be saved by removing infected shoots and treating the bushes with fungicides. Therefore, inspection of rhododendrons must be carried out regularly in order to identify the disease at an early stage.
Often appear on rhododendrons and pests. These include:
- Furrowed weevil.
- Rhododendron leafhopper.
- Rhododendron bug.
Fight pests by spraying the bushes with insecticides. Affected leaves must be collected and destroyed, as insects are often carriers of diseases.
Conclusion
Evergreen rhododendron can be a wonderful garden decoration. It is believed that the plant is capricious and quarrelsome, caring for it is difficult and time-consuming, but this is not so. Most of the difficulties are not related to the plant itself, but to unsuitable conditions for its growth. If you follow all the recommendations for choosing a place, the requirements for soil composition and care, the evergreen rhododendron can be grown quite calmly, even in conditions that are not quite suitable climate.