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Rhododendrons are a fairly extensive genus of ornamental shrubs and subshrubs, including more than 600 species. Due to their unpretentiousness of cultivation and excellent appearance, these plants are widely used to create flower arrangements, as decoration of parks and squares, and in ornamental gardening. Of particular interest to gardeners is evergreen rhododendron. It fully combines all the decorative qualities of this plant, and its 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 Ericaceae family. Many gardeners may know this shrub under the name azalea, but this is not entirely correct. Azaleas are a separate subspecies of rhododendrons, and among them there are also many evergreens.
A full description of evergreen rhododendrons is given in the table:
Parameter | Meaning |
Plant type | 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 resemble bells in shape. Collected in cap-shaped inflorescences of 6-20 pieces. The colors can be very different: white, pink, purple, yellow, etc. |
Flowering time | May June |
Seeds | Collected in fruits - boxes. Ripens in late August or early September |
Varieties of evergreen rhododendrons
Of the many species of rhododendrons, only a small part are deciduous shrubs. The rest do not shed their leaves for the winter, but only roll them up 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 lilac flowers are collected in large inflorescences of 10-20 pieces. The bush is dense, the crown diameter can reach 2 m. Based on this variety, a large number of frost-resistant hybrids of various colors have been bred.
English Roseum. One of the well-known hybrids obtained from the Katevbinsky rhododendron. It grows in a dense bush, the height and diameter of the crown of which can reach 2.5 m. The flowers have a characteristic mauve color with orange specks. The dome-shaped inflorescences usually contain 8-10 flowers. Below in the photo is the hybrid evergreen rhododendron English Roseum.
The variety has good resistance to adverse weather conditions and tolerates frost, rain and drought. Blooms in May-June.
Karens . The plant belongs to the Japanese azaleas. Forms a dense compact bush with a diameter and height of up to 1.5 m. The flowers are reddish-purple, with dark specks.
A distinctive feature of the variety is the strong aroma of flowers. Japanese azalea Karens blooms in May-June.
Nova Zembla. Another hybrid of Katevbinsky rhododendron. The bushes are distinguished by their respectable size - 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 reminiscent of peony flowers.
The Nova Zembla evergreen rhododendron 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, with a diameter of up to 1.2 m. It blooms with large (up to 9 cm) purple flowers in the shape of a wide bell with a characteristic golden center. The cap-shaped inflorescence can contain from 9 to 18 flowers.
Flowering begins in May, sometimes the evergreen rhododendron Marcel 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 to only 1-1.2 m. The flowers are medium-sized, 5-6 cm, pale lilac in color with golden freckles. Collected in hats of 15-20 pieces.
The winter hardiness of the variety is good, down to -25 °C.
Lita. A fairly 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 pieces. The color is pink with a purple tint; on the upper petal there is a blurred spot 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 Rhododendron Katevbinsky. 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 pieces.
The flowers have a characteristic red-brown spot. Winter hardiness – up to – 26 °C.
Pohyolas Doter (Podjola Doter). One of the most winter-hardy varieties of evergreen rhododendrons. Hybrid variety of Finnish selection. The bush grows to about 1 m. The crown is quite dense and wide. The flowers are light purple, almost white, with a reddish corrugated edge. Collected in inflorescences of 8-12 pieces.
Rhododendron evergreen 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 bush up to 1-1.2 m high. The flowers are bright, juicy, raspberry-pinkish, with orange splashes. Collected in inflorescences of 8-12 pieces.
Evergreen rhododendrons Helliki have several subvarieties, differing in color: Red, Helsinki University (pink), The Hague (purple-pink). All of them have excellent winter hardiness - up to -34 °C.
Planting and caring for evergreen rhododendrons
In the wild, rhododendrons grow primarily in regions with subtropical and temperate climates.Some species of this shrub are also found in Russia, for example, in southern Siberia and the Caucasus. To successfully grow evergreen rhododendrons in other climates, they will require some care.
Selection and preparation of a landing site
Evergreen rhododendrons do not like bright light; this can cause foliage burns. Therefore, to plant them, it is better to choose a place where the sunlight will be diffused. The area should be well protected from cold winds. 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 rhododendrons may have competition with shallow-rooted linden, maple or chestnut trees.
Seedling preparation
Saplings of evergreen rhododendrons can be purchased in specialized stores or nurseries. They are usually sold 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 coating, etc.).
Rules for planting evergreen rhododendrons
Evergreen rhododendrons can be planted in spring and autumn. In spring, planting can begin after the snow has completely melted and the soil has warmed up to + 8-10 ° C. In different regions, this time may fall in April-May. Autumn replanting can be done in September-November.Evergreen rhododendron tolerates replanting well, so you can plant it and replant it at another time, if it does not bloom.
The size of the planting hole should be twice as large as the volume of the seedling's root system. A layer of drainage must be placed at the bottom. To do this, you can use fragments of brick, expanded clay, and large crushed stone. Ordinary soil is not suitable for evergreen rhododendron, so for planting it is necessary to prepare a sufficient amount of soil substrate in advance. It must have a pronounced acidic reaction, so its composition must include high-moor peat and pine litter.
On the day of planting, the container with the seedling is spilled generously with water. This will make removing the plant much easier. The seedling, together with a lump of earth on the roots, is placed in a planting hole strictly vertically and covered with soil substrate, periodically compacting it. In this case, the root collar of the plant should be flush with the surface of the earth. After the hole is completely filled, the seedling is shed generously with water, and the root zone is mulched with peat or fallen pine needles.
Educational video about planting and caring for rhododendrons:
Watering and fertilizing
Evergreen rhododendrons love moderately moist soil, but excessive watering can lead to stagnation of water in the roots and their rotting. The condition of the leaves can serve as a guide. If they begin to lose their natural shine, 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 acidify it slightly.
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, you can feed plants with nitrogen-containing mineral fertilizers, for example, ammonium sulfate. Then the application of nitrogen should be stopped. Further fertilizing is carried out only with potassium and phosphorus complex fertilizers, so as not to stimulate excessive growth of green mass.
Trimming
The rhododendron bush is quite dense and compact, so, as a rule, it is not formed. Pruning can be carried out only for sanitary purposes, in order to clean the plant from broken or dried branches, as well as diseased or pest-damaged shoots. Periodically, the bushes need to be rejuvenated by cutting out perennial shoots and growing younger stems instead. This type of pruning of evergreen rhododendrons is carried out in the spring, before flowering begins, along with other care work. In this case, no more than ¼ of the bush is removed. Large cuts must be covered with garden varnish.
Some gardeners remove faded inflorescences by trimming them immediately after flowering. This measure helps the plant to redistribute nutrients and direct them not to laying and ripening seeds, but to the formation of new flower buds. Next year the flowering of such bushes will be more abundant.
How to prepare an evergreen rhododendron for winter
Preparation for winter is an essential part of caring for evergreen rhododendrons in the fall. In winter, plants can suffer not only from low temperatures, but also from the weight of adhered snow and cold wind. To prevent this, a fence - a house - is installed around the bush. 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. A 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 to preserve the bush in winter will not be superfluous.
The roots of evergreen rhododendrons are located close to the surface, so before wintering the root zone should be insulated. This can be done using peat, spreading it in a layer of 15-25 cm.
Why do evergreen rhododendron leaves 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 evergreen rhododendron is associated with the natural change of leaves. The leaves live for 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.
- Incorrect landing. Reddening of evergreen rhododendron leaves a short time after planting or replanting indicates unsuitable conditions for its growth. This may be direct sunlight, lack of moisture, etc.
- Phosphorus deficiency. Despite frequent feeding, the plant may experience a lack of this element. You can quickly replenish phosphorus deficiency 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 feeding is done several times a season.
Various diseases can also cause changes in the color of evergreen rhododendron leaves, 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;
- dividing 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. The germination rate of rhododendron seeds is good. The substrate must be periodically moistened with acidified softened water, and the growing seedlings must be illuminated with phytolamps, providing them with 12 hours of daylight. Plants are kept in containers for up to 3 years, taking them out into the open air only in the summer. Only then are the seedlings planted in open ground for growing.
The seed propagation method is the most time-consuming and labor-intensive, since seedlings require 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, acidic peat and coniferous soil. This soil mixture is best purchased at a specialized store. The cuttings are planted at an angle of 30°. After this, the substrate is moistened, and the container is covered with film and put in a warm place.
Evergreen rhododendrons take quite a long time to take root, from 4 to 5 months. All this time it is necessary to maintain an optimal temperature (+ 25-30 ° C), as well as high humidity. You can speed up the process by additionally illuminating the cuttings with phytolamps, increasing the daylight hours to 15-16 hours. As they grow, the seedlings are carefully transferred to larger containers, being careful not to disturb the lump of earth on the roots. Rhododendron grows for 1-2 years, after which it can be planted in a permanent place.
It is quite simple to obtain cuttings from the mother bush of evergreen rhododendron. To do this, you can use 2 methods:
- Bend several side shoots to the ground, secure 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 sliver or branch is inserted into the split. This technique ensures faster and more active rooting. Regular watering ensures rapid growth of the cuttings' own root system. In the fall, the cuttings are not cut off so as not to weaken them before wintering; they overwinter together with the mother bush. Transplantation is carried out in the spring.
- Cover the base of the bush with a large amount of soil substrate. In this case, part of the side stems will take root on their own with sufficient watering.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, heavily grown 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 irregularities in care, weather factors, or poor-quality planting material. The greatest danger to these plants is fungal diseases. These include:
- Rust.
- Late blight.
- Spotting.
- Gray rot.
Diseases can be recognized by changes in leaf color, the appearance of putrefactive deposits, white or brown plaque, and changes in the shape of shoots or leaf blades.
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 to detect the disease at an early stage.
Pests often appear on rhododendrons. These include:
- Furrow weevil.
- Rhododendron leafhopper.
- Rhododendron bug.
Pests are controlled by spraying the bushes with insecticides. Affected leaves should be collected and destroyed, since insects are often carriers of diseases.
Conclusion
Rhododendron evergreen can be a wonderful garden decoration. It is believed that the plant is capricious and uncooperative, 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 location, requirements for soil composition and care, evergreen rhododendron can be grown completely calmly, even in conditions of a not entirely suitable climate.
