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Smirnov's rhododendron is an evergreen broadly spreading tree-like shrub. The plant looks great on the site and as part of a free-growing hedge, and as a single shrub, and as a participant in a flower arrangement. Subject to certain conditions, Smirnov's rhododendron grows well in Moscow and the Moscow region.
Description of Smirnov's rhododendron
Smirnov's rhododendron (R. Smirnowii) grows in the lower and middle belt of the Adjara mountains and in the Artvin district of Turkey. This shrub in nature grows up to 3 m, in culture a little more than 1 m. The leaves are large, glossy, oblong, dark green, red-pink bell flowers are collected in densely blooming compact inflorescences. In the Moscow region, Smirnov's rhododendron begins to bloom in the first half of June. The flowering of the plant lasts three months. The fruits are tied in June, the seeds ripen in late autumn - early November. This shrub is durable, with proper care it can live for more than 30 years. It is frost-hardy, with light cover it calmly survives winters in central Russia. For the first time, Smirnov's rhododendron appeared in the St. Petersburg Botanical Garden in 1886.
Growing conditions for rhododendron Smirnov
Inexperienced gardeners, having seen the luxurious photos of the blooming Smirnov rhododendron and having read a brief description of the characteristics of the plant, decide to decorate their plot with them, and then they will be disappointed. A shrub that is improperly planted weakens and dies. This is a shame, because these beautiful ornamental plants can be grown in the Moscow region, and in Nizhny Novgorod, and in Volgograd.
It is not difficult to create comfortable conditions for evergreen rhododendrons:
- You need to plant rhododendron in an area protected from wind and sun. Better under the protection of tall plants, so that a thin, sparse shadow is formed.
- This shrub is hygrophilous, but does not tolerate stagnant water. Therefore, they choose a site that does not suffer from melt water and autumn rains.
- Rhododendron prefers acidic, permeable, light soil.
Planting and caring for Smirnov's rhododendron
Planting the evergreen Smirnov rhododendron without taking into account its specific requirements leads to the appearance of weakened, diseased plants on the site, which even subsequent intensive agricultural technology cannot help.
Selection and preparation of the landing site
Rhododendron Smirnov loves sour, light soils. The planting pit is filled with a mixture of sour peat, sand and coniferous soil (3: 1: 2). Coniferous soil (half-decayed needles) is collected in a pine forest. If the soil is clay, drainage from sand, stone or broken brick is arranged at the bottom of the pit.
Seedling preparation
Before planting, a rhododendron seedling, together with an earthen lump, is dipped into a solution of sodium humate, a clay mash or water, and wait until the release of bubbles stops. Then the plant is taken out and the roots are straightened, otherwise the seedling will not take root and will die in winter. Flowers, if any, are removed.
Landing rules
Smirnov's rhododendrons are planted in early spring or early autumn.It is better to buy plants with a closed root system, so the roots and soil fungi are preserved, without which this shrub cannot grow. The depth of the planting fossa is 30-40 cm, the diameter is 60 cm. They are planted flush with the surface of the coma (up to the level of the root collar). After planting, the plant is watered abundantly, and the trunk circle is mulched with chopped pine bark (needles) or peat.
Watering and feeding
So that the shrubs do not suffer from dry air in extreme heat, they are sprayed every evening. The topsoil under the rhododendron should always be moderately moist; regular watering (2-3 times a week) and mulching will help here. Do not remove from under the bushes and their own litter. After watering, the soil is loosened.
Fertilizers:
- Adult plants are fed in the spring with special mineral fertilizers for rhododendrons or a solution of kemira (20 g per bucket of water, consumption per 1 sq. M.), Compost or rotted mullein is added.
- Young shrubs need liquid complex fertilizers in low concentration, which are used in early spring and summer after flowering.
- Twice a year, the soil under the rhododendrons is artificially acidified with a dry mixture of 30-40 g of ammonium sulfate, superphosphate and potassium sulfate in a ratio of 2: 1: 1.5 (during active growth) and a mixture of 60 g of phosphorus and 15 g of potassium (after flowering ).
Pruning
Sanitary pruning is done as the buds swell to see which twigs or shoot tips are frozen in winter. Broken, damaged shoots are cut out, the bushes are slightly thinned out. To give the crown density and compactness, formative pruning is carried out in May, but it delays the growth and flowering of Smirnov's rhododendron.
Preparing for winter
The shrub is abundantly shed before the onset of cold weather (before the first frost), then the trunk circle is mulched and covered. It is better to use black opaque film to protect the plant from sunburn in early spring and spruce branches to protect it from the cold. It is important to protect the plant for the first 2-3 years of life. The shelter is removed in early May.
Reproduction
The climatic conditions of Moscow and the Moscow region, according to reviews of professional flower growers, allow you to independently plant and grow Smirnov's rhododendron in the garden.
Reproduction methods: seeds, cuttings, grafting on the Pontic rhododendron.
Sow rhododendrons in winter. Coarse river sand is added to the peat mixture at the rate (3: 1). Sowing containers are chosen shallow (5-6 cm) with drainage holes. The soil is moistened, slightly compacted and the seeds are spread on the surface at a distance of 1.5-2 cm from each other. Then the containers are covered with glass and germinated in the light. Crops need daily ventilation, soil moisture. The first shoots appear in a month.
Some nuances:
- pre-sowing treatment of seeds is not required;
- germination temperature +200FROM;
- seedlings bloom after 6 years.
Semi-lignified stems, 50-80 mm long, are suitable for propagation by cuttings. The lower leaves are removed, and the cuttings are immersed in solutions that stimulate root growth. After that, they are planted in a soil mixture of sand and sour peat (1: 3) and covered with a glass dome. Rooting takes 3 to 4.5 months. Cuttings are grown in boxes filled with peat and coniferous soil in a ratio (2: 1). In winter, the boxes are kept in a bright room at a temperature of +120C, in the spring, the containers are taken out into the street and buried in the garden area, where they grow for another 1-2 years. Only after that, the rooted cuttings are transplanted to a permanent place.
Diseases and pests
Rhododendron plants are gentle, attractive to diseases and pests. To avoid the death of plants, regular inspection of the bushes and timely treatment are required.
Pests:
- Rhododendron bug... Its presence can be recognized by the black-brown dots on the back of the sheet.
- Spider mite - feeds on leaf juices. Infection with them is easy to identify by the appearance of plants. The underside of the leaves is covered with a thin web, and they themselves darken and fall off.
- Furrowed weevil... Adult insects are dangerous for the aerial part of the plant, the larvae for the root system. Larvae and adults are insensitive to insecticides.
- Narrow-winged miner moth... Caterpillars that feed on leaves cause harm. As a result, the leaves become dry, brittle and fall off. Scare away the insect by fumigating or spraying the bushes with sulfur.
- Rhododendron fly... You can notice the defeat by the light spots on the leaves. This pest is destroyed by spraying with nicotine sulfate.
Diseases:
- Tracheomycosis - damages the vascular system of the bush, leads to rotting of the rhizome. Treatment: spraying with Bordeaux liquid.
- Late blight rot... It affects the stems and the root collar of the bush, they become covered with brown or purple spots, then the rhizome rots, then the bush dies.
- Phylostictic, pestalocious, septoria spot of rhododendron... All diseases are characterized by the appearance of spots on the leaves. In the first case - the color of the spots is brown, in the second - dark brown or gray with a dark rim along the edges, in the third - the spots are reddish, gradually whitening in the center. Treatment: spring spraying with Bordeaux liquid, cumulos, fungicide treatment.
- Rhododendron rust... The leaves turn red, as if covered with rust spots. Treatment: copper preparations.
- Rhododendron root bacterial cancer... On the root collar and roots of the bush, gradually darkening round growths appear, which eventually become hard. Plants begin to rot, bloom poorly and die. Treatment: heavily affected shrubs are burned along with the roots, slightly affected (until the growths harden) are sprayed with Bordeaux liquid.
- Chlorosis of rhododendrons, characterized by the appearance of yellow spots on the leaves. The cause of the disease: increased soil acidity, depleted soil. Treatment: shrubs are sprayed with a mixture of magnesium sulfate and ferrous sulfate (7 g of each substance per 1 liter of water).
Conclusion
Smirnov's rhododendron is a very beautiful evergreen shrub, its high decorative qualities attract the attention of landscape designers and just flower lovers. At the same time, Smirnov's rhododendron is winter-hardy, not too demanding and can grow in central Russia.
A long time ago at VDNKh, behind the Mechanical Engineering pavilion, there was a section with Smirnov's rhododendrons. Their height was more than 1.5 meters, almost 2 m. The plants are powerful. For the winter, the branches were tied up and that's it. But the ground under them was sprinkled with manure. Next to them, there were some more of the same size, but their leaves were broader in olive color.