Rhododendron: planting and care in the open ground, types and varieties with photos
Rhododendron (Rhododendron) is a representative of the Heather family. This genus is represented by shrubs and trees, which are deciduous, semi-deciduous and evergreen. According to various sources, this genus unites 800–1300 species, including azaleas, which are very popular among gardeners, they are also called “indoor rhododendron”. The name of this plant includes 2 words: "rhodon", which translates as "rose" and "dendron" - meaning "tree". In this regard, rhododendron means "a tree with roses," or "rosewood." The fact is that azalea flowers are similar in appearance to roses. In the wild, rhododendrons are most prevalent in the Northern Hemisphere (in southern China, the Himalayas, Southeast Asia, Japan, and North America). They prefer to grow in the coastal zone of the seas, rivers and oceans, on the northern slopes of the mountains and in the shade of undergrowth. Some species reach a height of 0.3 m, while others are creeping shrubs. Flowers of various species of this genus differ from each other not only in color, but also in shape and size. For example, the largest flowers in diameter can reach 0.2 m, while the smallest ones are simply tiny. To date, there are approximately 3 thousand varieties, forms and varieties of garden rhododendron.
Features of Rhododendron
Garden rhododendron is a shrub. Different species may differ from each other in the size and shape of the leaf plates, which are biennial, annual and perennial, petiolate or sessile, sequentially, serrate or whole-edge, obovate or ovate. This plant is relatively popular in all countries of the world due to its decorative foliage, as well as beautiful flowers, which are part of racemose or corymbose inflorescences, which look like amazingly beautiful bouquets. Flowers can be painted in pink, purple, white, red or purple. The shape of the flowers depends on the type and variety of plants and is funnel, tubular, bell-shaped or wheel-shaped. In some species, the flowers have a pleasant smell. The fruit is a five-leaved multi-seeded box, inside of which are two-millimeter seeds. The superficial compact root system of this culture consists of a large number of fibrous roots. Due to the fact that the root system is superficial, rhododendron transplantation is quite easy, and the plant tolerates it well. This shrub is considered a wonderful early spring honey plant.
Rhododendron: choice of place, landing, care
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Rhododendron planting in open ground
The choice of time and place of landing
In middle latitudes, it is recommended to cultivate only those types of rhododendron that are characterized by high frost resistance. You can plant a plant in open soil from April to the second half of May, and even in September – November. Experienced gardeners are engaged in planting rhododendron throughout the entire growing season, with the exception of the flowering time of such a shrub, and you can not do this for 7-15 days after flowering.
For planting, you should choose a shaded area located on the north side of the structure. Soil should be well-drained, loose, contain a large amount of humus and be acidic. If the plot has a groundwater depth of less than 100 cm, then to plant this shrub you will have to make a raised bed. Rhododendron can be planted next to trees such as oak, pine, larch, as their root system goes deep.This shrub is not recommended to be planted next to chestnut, maple, elm, linden, alder, willow and poplar, because their root systems are at the same depth as rhododendron, so the latter will lack the necessary amount of nutrients and moisture. If you still have to plant a rhododendron next to one of the trees listed, then the edges of the planting pit will need to be protected by digging slate, ruberoid or polyethylene into the soil. The best neighbors for this crop are a pear and an apple tree.
Prepare a hole for planting, so its depth should be about 0.4 m, and its diameter should be about 0.6 m. Pour a soil mixture consisting of 3.5 buckets of loam into it (you can replace a pair of clay buckets), as well as 8 buckets of peat. It should be mixed thoroughly. Then the soil mixture poured into the pit must be well compacted. After that, a hole is made in it, the size of which should be equal to the size of the root coma of the planted plant. Immediately before planting, the seedling must be immersed in a container filled with water. And it is necessary to pull it out only after air bubbles stop coming to the surface of the water. After this, the root system must be placed in the hole, which is filled with soil mixture, it must be very well compacted so that there are no voids. In a planted seedling, the root neck should be at the same level with the surface of the site. Planted plants need abundant watering. If the rhododendron was planted in dry soil, then the abundance of watering should be such that the earth is wet to a depth of 20 centimeters. Then the surface of the trunk circle should be covered with a layer of mulch (oak leaves, pine needles, peat or moss), while its thickness should be 50-60 mm. If there is a large number of buds on the seedling, then part must be cut off, in this case the forces of the plant will be directed to rooting, and not to magnificent flowering.
If only one bush of rhododendron is planted on a spacious plot, then the wind is able to loosen the seedling. To avoid this, it is necessary to establish a support, while tilting it must be directed towards the direction of most often blowing winds. Then a planted plant is tied to a support. After the plant has taken root, the support can be removed if desired.
Bought RODODENDRON. How to plant properly? Acidify the soil
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Rhododendron needs good care. It must be sprayed, watered, fed, weeded in a timely manner, trimmed to form, and if necessary protected from pests and diseases. Loosening or digging the surface of the soil under the bushes is impossible due to the surface location of the root system of the plant. Weeding must be done manually; using a chopper for this purpose is strictly prohibited.
This culture is especially important level of atmospheric and ground moisture compared to other garden plants, especially during budding and flowering. Rhododendron is very important to water correctly, because it has a significant impact on the laying of flower buds of the coming season. It is necessary to water the plant with exclusively soft water (standing or rain). Some gardeners soften and acidify the water very simply, for this they mix it with horse peat 24 hours before watering, you need to take a few handfuls. According to the state of leaf blades, you can determine how often you should water this shrub. The plant needs watering if the foliage becomes dull and loses turgor. During irrigation, the ground should be saturated to a depth of 20 to 30 centimeters. But when watering, it is also very important that the liquid does not stagnate in the soil, since the root system reacts extremely negatively to this.When water stagnates, rhododendron behaves in exactly the same way as when there is a lack of moisture, namely, sheet plates are folded and lowered. To avoid waterlogging, it is necessary to water the shrub in the dry hot period as always, but it needs to be moistened quite often from the sprayer using soft water.
Since bushes most often naturally have the correct shape, there is no need for a strong formative pruning. Typically, a plant needs pruning if the shrub has become excessively tall, if anti-aging pruning is needed, or stems damaged by frost need to be cut.
What are the rules for pruning an adult shrub? Pruning of stems is carried out in the spring, while you need to catch it before the sap flow begins. Slices on branches, the thickness of which is from 20 to 40 mm, must be smeared with garden var. The awakening of the sleeping buds on the stems begins after 4 weeks, at the same time, the beginning of the renewal process, which lasts throughout the year. If the shrub is very badly damaged by frost or is old, then it should be shortened to 0.3-0.4 meters, with one half of the bush being cut in the first year, and the second in the next year.
Such plants have one very important feature. So, in one year their flowering and fruiting is distinguished by its abundance, while the next - it bears fruit and blooms much more poorly. However, this frequency can be corrected. To do this, after flowering is completed, it is necessary to break out all faded inflorescences. In this case, the shrub will direct all stored forces and nutrients to the laying of the flower buds of the next season.
Even shrubs planted in the current season need to be fed. For the first time in a season, the plant is fed at the beginning of the spring period, while the last time is in late July, when the plant fades and young stems begin to grow. Experts recommend using liquid fertilizers to feed this crop, which should include horn flour and half-rotten cow manure. To prepare such a fertilizer, manure should be combined with water in a ratio of 1:15, then it should be infused for several days, only after that they can feed shrubs. Before feeding rhododendron, it must be properly watered.
Such plants need acidic soil, in this regard, choose mineral fertilizers should be those that do not disrupt the reaction of the environment. So, it is recommended to use superphosphate, phosphate, potassium nitrate and sulfate, ammonium sulfate, calcium sulfate and magnesium, while taking them in a weak concentration (1.2: 1000). A solution of potash fertilizers should be even weaker.
Recommended fertilizer application:
- at the beginning of spring, organic or mineral fertilizers containing nitrogen are added, while 50 grams of magnesium sulfate and the same amount of ammonium sulfate are taken per 1 square meter of the plot;
- in the first days of June, when the plant fades, 20 grams of potassium sulfate and superphosphate, as well as 40 grams of ammonium sulfate are added per 1 square meter of the plot;
- the third time rhododendron is fed in July, while 20 grams of potassium sulfate and superphosphate are taken per 1 square meter of the plot.
Diseases and pests
Most often, mealybugs, scale insects, spider mites, bedbugs, weevils, rhododendron flies, and also slugs and snails settle on this shrub. When gastropods appear on the bushes, they should be collected manually, and for prophylactic purposes, the plant is sprayed with a solution of the fungicidal preparation Tiram or TMTD (8%).
If rhododendron bugs, spider mites or weevils settled on the rhododendron, then it must be sprayed with Diazinon.In this case, when the weevils are affected, not only the bush is processed, but also the surface of the earth near it. In order to get rid of the rest of the pests, they use Karbofos, while you need to follow the instructions in the instructions.
Most often, such a plant is sick with fungal diseases, for example: cancer, rust, chlorosis or leaf spot. Most often, such diseases develop as a result of insufficient aeration of the root system. When damaged by rust and spotting, the bush must be sprayed with copper-containing preparations, for example, Bordeaux mixture. In case of chlorosis, the bush changes its color to yellow, in this case, it is necessary to pour iron chelate into the water for irrigation. If rhododendron is ill with cancer, then the affected stems must either be cut to healthy tissue or removed altogether. For prevention in the early spring and late autumn, the bushes should be sprayed with a Bordeaux mixture.
This plant can be propagated by seeds or vegetative methods: layering, grafting, dividing the bush and cuttings. The quickest and easiest way to propagate such a plant is by layering.
For sowing seeds, use plates that are filled with moistened peat or heather soil mixed with sand (3: 1). After the seeds are sown, they are sprinkled on top with sand, which should be washed. Top containers should be covered with glass, and then they are transferred to a well-lit place. Crops need to be watered in a timely manner, ventilated every day, and also you need to regularly remove condensate from the glass surface. As a rule, the first seedlings appear after 30 days. When the seedlings form a pair of real leaf plates, they will need to be planted more freely using the 2x3 centimeter scheme. When transplanting, seedlings should be recessed in the cotyledon, this will form a strong root system. Seedlings in the first year of life must be grown in a cool greenhouse. In the second year, seedlings must be transplanted into open soil on training beds with garden soil mixed with a small amount of peat and sand. Such seedlings are characterized by relatively slow growth. Their first flowering can be seen only for 6-8 years.
Cuttings are also a rather complicated method of reproduction. For harvesting cuttings using semi-lignified stems. The length of the cuttings can vary from 50 to 80 mm. The lower leaf plates with chopped cuttings should be cut off. At the same time, the lower sections must be immersed in a solution of a root growth stimulating agent (for example, heteroauxin) for 12–16 hours. For rooting, cuttings are planted in a substrate consisting of sand and peat (1: 3). Then the container on top must be covered with a transparent dome. Rooting cuttings is a long and difficult process. So, the rooting of evergreen species lasts from 3 to 4.5 months, and deciduous - 6 weeks. For growing, cuttings are planted in boxes filled with a substrate consisting of pine needles and peat (1: 2). During the winter period, the cuttings should be in a well-lit and cool (from 8 to 12 degrees) room. With the onset of spring, a box with cuttings should be buried in the garden. There they will grow another 1 or 2 years, only after that the cuttings can be transplanted to a permanent place.
The easiest and most natural method of propagation of this culture is the instillation of layering. In spring, you should choose a low-growing young flexible shoot, it must be bent and laid in a prepared groove, the depth of which should be at least 15 centimeters. The middle part of the stem must be fixed in the groove, pinning it. Next, the groove is filled with garden soil connected to peat. The top of the stem remaining on the surface must be tied to a vertically mounted peg. When watering the bush itself, one should not forget to moisten and layering.In autumn, or with the onset of next spring, cuttings must be cut off from the parent plant and planted in a permanent place. This method is great for propagating deciduous rhododendron.
Growing stocks. Rhododendrons
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Rhododendron after flowering
If drought is observed in autumn, then the rhododendron will need regular abundant watering, for example, 10-12 liters of water should be poured under 1 bush. If systematic rains are observed in autumn, then such plants need not be watered. In November, the root system of the bush should be insulated, for this the surface of the trunk circle should be mulched with a layer of peat.
If rhododendron is grown in mid-latitudes, then after the first frosts the bushes should be insulated. To do this, between the branches of plants, pine or spruce branches are shoved, and the shrub itself is pulled together a little with twine. Then it should be covered with burlap. Remove bags from plants should be in early spring after the snow cover has melted, and choose a cloudy day for this. If rhododendron is cultivated in a region with a fairly warm climate, then it does not need shelter for wintering.
How to cover evergreen rhododendrons for the winter. Site "Garden World"
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Types and varieties of rhododendrons with photos and names
There are a very large number of rhododendron species. Below will be described those species that are cultivated by gardeners, as well as the most popular garden varieties.
Rhododendron Daurian (Rhododendron dahuricum)
Under natural conditions, this species is found on the rocks and in coniferous forests of Northeast China, Eastern Siberia, Primorsky Krai, Korea and Northern Mongolia. This medium-sized evergreen shrub is highly branched, its height can vary from 200 to 400 cm. The color of the bark is gray. The branches are directed up. Brownish-red thin shoots closer to the tips have pubescence, which is a short pile. The length of small leathery sheet plates is about 30 mm, their front surface is smooth, and the inside is scaly. The color of young leaves is pale green, and over time they become dark green, in the autumn they turn green-red or brown. In winter, only a not very large part of the foliage flies around. Flowering is quite lush and lasts about 20 days. The flowers bloom before the foliage opens. They are large, have a funnel shape, pink-purple color, and in diameter reach 40 mm. In autumn, repeated blooming is sometimes observed. This species is highly resistant to frost, and it also reproduces well with green cuttings. There are 2 varieties:
- evergreen form - the color of the foliage is dark green, and the flowers are lilac-purple;
- early garden hybrid - this low-growing plant blooms very luxuriantly, flowers across reach 50 mm, they open very early and are painted in a rich red-blue color, this form is less frost-resistant compared to the main species.
This evergreen shrub grows on rocky slopes and in the mountain forests of the Far East, as well as the northeastern foothills of Tibet. The height of the branchy bush can reach up to 50 cm. On the surface of the shoots there is pubescence, consisting of glandular pile. Matte dense green leaf plates have an oblong-elliptical shape in length and width they can reach about 20 mm. Their front surface is bare, and on the wrong side there are scales, because of which it has a red color. Scutes consist of 7–15 flowers, reaching 15 mm across; they are painted in various shades of pink. This species is listed in the Red Book of Buryatia.
Japanese Rhododendron (Rhododendron japonicum)
The native land of this species is Japan, or rather, the island of Honshu, where it prefers to grow on sunny mountains.This species is one of the most beautiful deciduous rhododendrons. The height of a branched shrub can reach 200 cm. The stems are bare or on their surface there are silver bristles. The green leaf plate has an oblong-lanceolate shape, and there is soft pubescence on the front and back surfaces. In autumn, foliage turns red-orange. The brushes consist of 6–12 fragrant bell-shaped flowers, reaching a diameter of 80 mm and having a red-scarlet or orange color. Of all the species grown in mid-latitudes, this species is the most beautiful. It has high frost resistance, and also perfectly propagated by seed and cuttings.
Caucasian Rhododendron (Rhododendron caucasicum)
In nature, this species is found on the territory of the Caucasus. This not very tall shrub is evergreen, its branches creep. Leathery dark green leafy plates, located on fairly thick long petioles, have an oblong-oval shape. Their front surface is bare, and the inside is felt-red. On the hairy peduncles are brushes consisting of 8-10 fragrant flowers having a funnel-bell-shaped shape and a pale green color, green spots are inside the pharynx. Decorative forms:
- pink-white - flowering begins earlier than in the main species;
- brilliant - the color of flowers is dark pink;
- golden yellow - on the surface of yellow flowers there is a pale green speck;
- straw yellow - light red spots are located on the surface of yellow flowers.
Also, gardeners cultivate such species as: Albrecht's rhododendron, Atlantic, Vasea, holoflora, treelike, yellow, stiff-haired, western, golden, Indian, Kamchatka, Canadian, Caroline, Carpathian, carpal, gooey, short-fruited, blushing, largest, leafy, ke , Lapland, Ledeboura, small-leaved, marigold, sea-buckthorn, spiky, dense, Pontic, attractive, Bukhan, rusty, equally tall, pink, Sikhotin, slaly, dull, rooted, Yakushiman, etc.
This includes hybrids and cultivars that are cultivated by gardeners. Hybrid Rhododendron is a garden rhododendron. The following varieties are most popular:
- German cultivar Alfred. This variety was obtained by crossing Katevbinsky rhododendron with Everestin. This evergreen shrub reaches 1.2 m in height. The diameter of the crown is approximately 150 cm. Glossy dark green leafy plates have an oblong-elliptical shape. Dense inflorescences consist of 15–20 flowers of a saturated purple color, which have a green-yellow spot in diameter reaching 60 mm.
- Variety Blue Peter. It was bred by crossing the Pontic rhododendron. The bush reaches a height of more than 150 cm in height. The spreading crown has a diameter of about 200 cm. In diameter, lavender-blue flowers reach 60 mm, they have a corrugated edge, and on the upper petal there is a spot of dark purple color.
- Jackson. This English hybrid was obtained by crossing the Caucasian rhododendron and the Nobleanum variety. The height of the shrub is about 200 cm, and in the cross its crown reaches about 300 cm. There is a stunted form, the height of which does not exceed 0.8 m. The leathery oblong leafy plates have a green matte front surface and a brown back. Inflorescences consist of 8-12 flowers, which are pink in the process of opening, then it changes to white, and a yellow-white speck forms on one of the petals.
- Rose Marie. The Czech variety, which is obtained by crossing the magnificent rhododendron and Pink Pearl. The shrub reaches a height of 1.2 m, and the diameter of the crown is 150 cm.Leathery leaf plates have an oblong-elliptical shape, on the greenish front surface they have a wax coating, and the wrong one is green-blue, shiny. At the edges of the flowers are painted in a pale pink color, which in the middle is replaced by a deep pink with a purple tint. Compact spherical inflorescences consist of 6-14 flowers.
- Nova Zembla. This Dutch hybrid was bred by crossing the rhododendron of Katevbinsky and Perse Gloriosum. The height of the shrub is about 300 centimeters, and a loose crown in girth reaches about 350 cm. The stems grow almost vertically. Leathery glossy sheet plates are quite large. Dense inflorescences consist of 10-12 large flowers, reaching 60 mm across, they are colored red and have a black speck.
- Cunningham. This Scottish cultivar is a very popular variety of Caucasian rhododendron. The height of the bush is approximately 200 cm, and the crown in diameter reaches 150 cm. The length of the dark green leathery oblong leaf plates is about 60 mm, and the width is 30 mm. Dense inflorescences consist of 10 white flowers, on the surface of which there is a yellow speck.
Varieties and types of rhododendron.
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Rhododendron in the suburbs
Many unprofessional gardeners, seeing the gorgeous rhododendron in the picture, decide to decorate their garden plot with them at all costs. However, in most cases, having bought and planted the coveted bush on his plot, the gardener notices that his rhododendron is not as beautiful as expected, and besides, he gradually withers and dies. Therefore, most gardeners are wondering if it is possible to successfully cultivate such a thermophilic shrub in the suburbs? And in general, is it possible to grow such a plant in mid-latitudes unusual for it? If everything is done correctly, then it is quite possible.
Features landing in the suburbs
First of all, you should choose the right variety that can survive the rather frosty winter months. The fact is that heat-loving species and varieties, even if they are very well covered, will still freeze in winter. Deciduous species are very suitable for growing under such conditions: Japanese, yellow, Rhododendron, Schlippenbach, Vasaia, Canadian, Kamchatka, and Bukhan. Of the semi-evergreen, you can choose Ledebour's rhododendron. Ketevbinsky rhododendron (as well as its hybrids Alfred, Abraham Lincoln, Nova Zembla, Cunningham White), short-fruited, golden, largest and rhododendron Smirnova and its hybrids Gabriel, Dorothy Swift are suitable for growing in middle latitudes from evergreen species. Finnish breeders relatively recently obtained fairly winter-resistant varieties of Elvira, The Hague, Mikkeli. Hybrids of the Northern Light group Rosie Lights, Pink Lights, Spicy Lights and others also tolerate the harsh winter of the middle latitudes.
To buy a suitable seedling is not enough, it must still be planted correctly:
- Landing is done in the spring. The site should be in partial shade, and the distance between the seedling and any other plant should be at least 100 cm.
- For planting, it is recommended to buy a special soil mixture. If desired, it can be done at home, for this you need needles, garden land and peat. A complex mineral fertilizer must be added to the soil.
- The size of the planting pit should be a couple of times larger than the container in which the plant is located. If the soil is clay, then at the bottom of the pit you will need to make a good drainage layer of broken bricks, the thickness of which should be about 15 centimeters.
- After planting, the root neck of the plant should be at the same level as in the container.
- The planted plant needs abundant watering.
Features of care in the suburbs
To care for the rhododendron cultivated in mid-latitudes should be almost the same as for those plants that are grown in regions with milder climates. However, there are still several differences. Care Rules:
- For planting, acidic humus soil should be used. In those places where the roots will absorb nutrients, there should not be wood ash, dolomite, lime and other additives that can alkalize the soil.
- The surface of the trunk circle must be covered with a layer of mulch without fail. This is especially important because, due to horizontally located roots, loosening and digging of the soil around the plant is prohibited.
- In spring, the bush must be protected from the scorching rays of the sun. For this, gauze, mesh or fabric is suitable.
- It is very important to choose the correct watering mode. This plant should receive as much moisture as it needs. In the arid hot period in summer, the shrub should be watered 2 times in 7 days. If in the autumn there is rainy and quite warm weather, then young shoots begin to grow on the bushes, but they do not die in winter and die. In order to prevent such activation of stem growth, the bush should be treated from a finely divided spray with a solution of monophosphate or potassium sulfate (1%) and do this on a dry day. This will lead to a suspension of growth, as well as to stimulation of lignification of stems and laying flower buds for the next season. After the shrub has been processed, all watering must be stopped, even if there is drought and heat.
- If you are afraid that the bushes may be damaged by frost in winter, then they should be covered. For this, a frame of metal mesh is installed near the bush. It should be wrapped with a spanbond, which is fixed with ropes.
May 30, 2015 Flowering of rhododendrons in the suburbs
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Useful properties of rhododendron
Rhododendron is a very beautiful plant, and it also has healing properties that have been used for several years in both official and alternative medicine. The composition of the species rhododendron Daurian, golden, Adams, Caucasian includes andromedotoxin, ericoline, arbutin and rhododendrin. The composition of the foliage includes ascorbic acid, while in summer its concentration in the plant is greatest. Thanks to the substances included in the composition of such a plant, it has an analgesic, sedative, antipyretic, antibacterial and diaphoretic effect. It is also able to remove excess fluid from the body, eliminate edema, shortness of breath, palpitations, increase cardiac activity, and reduce venous and blood pressure.
But it should not be considered that this plant is absolutely harmless. Products made on the basis of rhododendron should not be used by people suffering from serious kidney disease and tissue necrosis, as well as pregnant and breast-feeding women. It is also recommended that you first consult a specialist before taking such a remedy for the first time.