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Rhododendron is a very attractive plant. The flower has earned the attention of gardeners for its amazing lush flowering. This can only be achieved with proper planting and proper care of the plant. I would like such beauty to be on the site even in a region with a difficult climate. Many people are hesitant to grow rhododendron, considering the plant to be not frost-resistant enough. Therefore, planting and caring for rhododendron in the Leningrad region is an important topic for gardeners in the North-Western region.
Features of growing and caring for rhododendrons in the Leningrad region
Flower growers are concerned about information that rhododendrons require special care and do not tolerate winter frosts well. However, in the Leningrad region there are gardens with mass plantings of these beautiful plants.
The key to successful cultivation of rhododendrons in the gardens of the Leningrad region is the competent selection of varieties. The choice should be among winter-hardy species, and then they need to be provided with proper planting and further care. Under natural conditions, the crop prefers to grow near forests and swamps. You can equally often find both single plants and large group plantings of rhododendrons.
Now there are many hybrids bred by breeders in order to obtain the desired characteristics. Therefore, choosing winter-hardy varieties of rhododendrons is not at all difficult.
The best varieties of rhododendrons for the Leningrad region
The flower belongs to the Heather family, which unites many species of trees, shrubs and indoor plants. Gardeners usually grow low-growing specimens of rhododendrons, almost creeping along the ground, or huge lush bushes, 3 to 7 m high. They are divided into three main types - deciduous, evergreen and semi-evergreen.
The best of them in regions with cold climates are hybrids with high winter hardiness. A selection of rhododendron varieties for the Leningrad region with descriptions and photos that tolerate low temperatures well, to help gardeners.
The first of them are representatives of the group of Katevba hybrids:
- Grandiflorum - a lush rhododendron with bright purple inflorescences. The height of an adult plant at the age of 10 years reaches 1.2-2.8 m. It has spherical inflorescences, slightly flattened, consisting of 12-19 flowers without fragrance. The color is lavender with yellow-red markings, the crown diameter is 3.0-3.2 m. A famous variety among gardeners in the Leningrad region due to its high frost resistance. Withstands temperatures down to – 32 °C.Flowering begins in early June.
- Nova Zembla - a red-flowered, evergreen variety of rhododendron. Just like the previous type of rhododendron, it begins to bloom in June. The flowers are bright, ruby red, with black inclusions inside the petals. Ball-shaped inflorescences of 13-17 original shaped flowers. The flowers have no scent; the leaves of the shrub are dark green, shiny, and shaped like an ellipse. Upon reaching the age of 10 years, rhododendron has a bush height of 1.6-1.8 m, and a crown width of 1.6 m. The maximum height that is recorded for the variety is 2.5 m. Winter hardiness is high, withstands temperatures down to -32 ° WITH.
- Polar Night (Polarnacht, Polar Night) characterized by rapid growth and longevity. In one place, a rhododendron bush grows well and blooms for up to 100 years. The plant is powerful, grows up to 2 m tall, the crown has the same size. The decorative value is very high; the purple color of the flowers makes the plant unusual. In addition to the rich color, the flowers have spectacular corrugated petals, the color of which changes depending on the degree of lighting. In the light they acquire a crimson hue, in the shade they become almost black. There are up to 20 pieces in an inflorescence, each ball resembles a bouquet. The height of an adult rhododendron is about 1.4 m. It begins to bloom in the Leningrad region at the end of May and can withstand frosts down to − 26 °C.
The following selection of rhododendron varieties for the Leningrad region from the group of Finnish selection. Gardeners love them for their high winter hardiness, low maintenance requirements and beautiful appearance. Can withstand temperatures as low as 30-40°C.
- The Hague differs in compactness and density of the bush. The bush is quite branched, forms a spherical crown of the correct shape.The diameter is 1.4 m. The height of an adult rhododendron reaches 1.5 m. Flowering in the Leningrad region begins in mid-June, the bush is covered with dense inflorescences of a juicy pink color with wavy edges. The petals have red-orange dots, one inflorescence consists of 15-18 flowers. Frost resistance is high.
- Hellikki - a variety for planting in the Leningrad region in shaded areas with acidic soil. Young shoots of the bush are soft and pubescent. Young leaves are also covered with white fibers. Rhododendron reaches a height of 1.2 m at the age of 10 years. Dark green foliage with bright pink-purple inflorescences provide a striking contrast in their combination. The inflorescences of the variety are located at the end of the branches and consist of 8-12 funnel-shaped flowers. It blooms from the end of May for a whole month. Withstands frosts down to – 34 °C. Does not tolerate waterlogging, but requires mulching of the root zone.
- Helsinki University - a hybrid with very powerful flowering. The height of the bush is 1.5-2.0 m, the diameter of the crown is 1.4-1.6 m. The inflorescences are conical in shape and consist of 12-18 flowers. Located at the end of the shoot. The flowers are pink with red splashes on the petals. A feature of the variety is considered to be very lush flowering even after harsh winters. Blooms in the Leningrad region from June. The variety is similar to another species - “Haaga”, but the color of the flowers and stamens of Helsinki University is lighter. It is considered a hardy variety with high frost resistance (up to - 40 ° C).
- Elvira for lovers of short rhododendrons. An adult bush has a height of only 0.6 m with a crown width of 0.6-1.0 m. The inflorescences consist of 6-10 flowers of a cherry-red hue, resembling bells in shape. Each flower has 6 ruffled petals.In the Leningrad region it blooms from mid-May to mid-June. The rhododendron variety is considered vulnerable in the spring; it loves good cover with snow. Requires care when choosing a planting site.
Planting and caring for rhododendron in the Leningrad region
To grow a luxurious bush in the North-West region, you must fulfill certain conditions:
- choose the right place for rhododendron;
- choose a winter-hardy, unpretentious variety;
- comply with planting deadlines;
- plant the plant correctly;
- perform basic care items.
The degree of flowering, health and appearance of the rhododendron depend on the quality of each stage.
When to plant rhododendron in the Leningrad region
Planting is allowed in spring or autumn. The main thing is that this event does not affect the flowering time and the 10-15 days before and after it. For a plant to develop well, it needs time to get used to a new place and conditions. Spring planting in the Leningrad region avoids the possibility of freezing of a young bush. If you plan to plant rhododendron in the fall, then in the Leningrad region it is recommended to take plants with a closed root system for these purposes.
Preparing the landing site
For rhododendron, it is important to choose the right place and prepare the soil. Heathers love acidic nutrient soil and partial shade. Water stagnation is unacceptable. Based on these preferences of rhododendron, an area with natural partial shade is chosen for planting in the Leningrad region. This may be in the vicinity of conifers, which will shelter the young rhododendron from heat and direct sunlight. The north or northeast side of the house also works well.Knowing the heat-loving nature of heathers, you shouldn’t risk planting them in bright sunlight. A close location to a body of water would be ideal.
The second condition for successful landing in the Leningrad region is the absence of strong winds. If there is no such area, then you will have to cover the bush with a hedge or a decorative screen. It is not worth planting rhododendrons completely under trees. Light partial shade does not mean constant shading. It is undesirable for rhododendrons to be adjacent to birch, spruce, and linden. But pine trees, oak trees and fruit trees are good additions.
The soil in the Leningrad region also needs to be prepared.
The heavy clay structure is especially unfavorable for rhododendrons. If you plan to plant several plants, then the place is prepared for all of them at once, and not for each bush separately.
The hole for the plant should be 70 cm in diameter and 50 cm deep. The bottom is covered with drainage to drain excess water. Sphagnum is placed in half the volume, then a quarter is filled with humus mixed with acidic nutrient soil. A good addition to the mixture would be fallen leaves or pine needles, pine cones. The soil should be loose.
Rules for planting rhododendrons in the Leningrad region
After preparing the hole and laying the soil mixture, the soil needs to be well watered. If the plant was purchased in a planting pot, then it is simply transferred with a lump of earth into the hole. The free space is filled with the remaining soil and watered again. The area around the trunk must be mulched on top with a layer of 5 cm.
In order to properly plant a rhododendron in the Leningrad region with an open root system, you will need to remove a layer of soil 1 m thick in the area allocated for planting. The resulting pit is shielded from the sides with natural materials. This must be done so that moisture and nutrients remain in the planting area when feeding the bushes. Place a drainage layer 20-30 cm thick on the bottom. Large crushed stone or broken brick will do. Pour sand (10-15 cm) on top.
Prepare a solution of the drug “Extrasol” (10%) and immerse the roots in it for 10-15 minutes.
Carefully place the seedling in the hole and cover it with soil. In this case, care must be taken not to deepen the root collar.
In the Leningrad region, a replanting option is possible for rhododendrons if the young plants are not planted in a permanent place. Bushes are replanted in the spring. The second period is the end of summer in August or the beginning of autumn in September. When replanting rhododendron, it is important to maintain the depth that was present when first planted. Then the plant is surrounded with a 10 cm thick layer of moss and pine needles.
Watering and fertilizing
There are basic nuances of care in the Leningrad region, without quality implementation of which it will not be possible to grow a luxurious rhododendron bush. When watering, it is necessary to maintain a golden mean. The plant loves moisture, but does not tolerate stagnation. Therefore, you need to monitor moisture absorption and maintain looseness of the soil. If stagnation occurs, then high-quality drainage is needed. To balance the moisture supply, gardeners:
- Rhododendrons are planted in the Leningrad region on high ridges.They are raised 10-15 cm above the average spring flood level.
- Be sure to add loam to the soil mixture. It prevents peat and pine litter from clumping together, which significantly reduces the quality of watering.
- Use melt or rain water. Plants react worst to tap water due to the presence of chlorine.
- The leaves are periodically irrigated by sprinkling. This is especially true during the dry, hot months of summer.
Another important event for gardeners in the Leningrad region is fertilizing. The most suitable feeding periods for rhododendron begin in the spring at the time of flowering and in the fall, 2 months before the first frost.
It is important to remember that conventional nitrogen fertilizers are ineffective for this type of plant. Gardeners in the Leningrad region need to use special compounds for acidic soils. Fertilizers are applied for the first time at the beginning of flowering of the bush. If you do this earlier, the nitrogen components will negatively affect the development of flower buds. They just start to crumble. Main nuances and nutrition schedule of rhododendrons in the Leningrad region:
- Nitrogen fertilizing at the end of March. 15-20 g of ammonium sulfate is enough for one bush. An alternative could be cow dung infusion.
- Phosphorus and potassium components are added in mid-June. The end of summer is not the best period. If you feed rhododendrons at this time, they will grow.
In addition, the bushes must be mulched with pine or spruce bark in a 3 cm layer. However, loosening is contraindicated for rhododendrons due to the close location of the roots to the soil surface.
Do not use ash, clay or lime when caring for plants. These substances change the acidity of the soil, which will not have the best effect on the life of the bushes. The optimal acidity level for rhododendrons is 4.5-5.0 pH.
Trimming
In addition to watering and fertilizing, it is very important to prune the rhododendron.
Pruning involves achieving several goals:
- Removing faded inflorescences. They continue to be pruned until seeds form. Thus, the gardener helps the plant save vital resources and stimulates the formation of new flower buds for the next season.
- Crown formation. Spring pruning in early March involves cutting off young shoots above dormant buds. At the same time, the crown of the rhododendron is formed in the form of a ball.
- Renewing a bush or reducing the crown. In this case, the shoots are cut off under the fork. The thickness of the removed branches is no more than 2-4 cm.
Protection from diseases and pests
In the Leningrad region, rhododendrons can be affected by fungal diseases. The most common are leaf spots, rust, and cancer. The first two diseases are removed with the help of copper sulfate, which is used to treat the plants. If the variety gets cancer, the affected shoots are removed and burned. Preventative treatments for the disease are done with Bordeaux mixture twice a year - in spring and autumn.
An important point that leads to infection is violation of agrotechnical requirements:
- poor soil aeration;
- excessive watering;
- lack of preventive treatments.
Among the pests in the Leningrad region, thrips, scale insects, whiteflies, spider and rhododendron mites, snails, and slugs should be noted. They need to be controlled with insecticides.
Preparing rhododendrons for winter in the Leningrad region
Frost protection is very important to maintain the viability of the plant. Methods of shelter in the Leningrad region are slightly different for different types of rhododendrons.
- Deciduous. The shoots are bent to the ground, but make sure that the buds do not come into contact with it. Sprinkle the planting areas with dry leaves or peat with a layer of 15 cm. This is necessary to protect the root collar.
- Evergreen varieties require shelter. It protects plants not so much from frost as from drying out. Rhododendrons begin to cover when the first frost occurs. Be sure to leave ventilation holes so that when the weather warms up, the plants do not rot.
The first year the bushes are covered with non-woven material. Lutrasil, spunbond and frame structures are used. In spring, rhododendron bushes open gradually, in several stages. They start in cloudy weather and continue to adapt the plants for 10-15 days to avoid sunburn.
Reproduction
There are only two main methods of propagating rhododendrons for Leningrad gardeners - seeds and cuttings.
Deciduous varieties prefer to be propagated in shifts. They ripen in September. Sowing begins in early spring, having previously germinated the planting material at a temperature of + 10-15 ° C. This usually takes 8-10 days. The soil for seedlings is prepared from a mixture of sand, peat and coniferous soil. After 2-3 leaves appear, the seedlings are picked and then grown in a greenhouse. Such rhododendrons begin to bloom after 5-10 years.
Lignified apical shoots are suitable for cuttings. The cutting diameter is 3-5 cm, the length is 3-4 internodes. Mixtures are prepared for rooting:
- peat soil + sand (2:1);
- heather soil + sand (2:1).
The material is harvested in July; leaves are always left at the top of the cutting. The lower end of the cutting is immersed in a Heteroauxin solution, then placed in the soil mixture. The lower part of the container in which rooting occurs must be heated with warm air. To do this, the containers are raised above the ground. Rhododendrons take root slowly. Transplantation is available only after a year. If the cuttings are immediately placed in the ground, then they are securely covered during the first winter. During the growth period of the cuttings, 3 pinches are made.
There is another method of propagating deciduous rhododendrons, in which they begin to bloom the next year - by layering. You need to dig in last year's shoots and water regularly. Use Heteroauxin solution once a month. Next autumn, the cuttings are separated from the mother bush.
Conclusion
Planting and caring for rhododendron in the Leningrad region is accessible even to novice gardeners. If you comply with agrotechnical requirements and monitor the condition of the bush, then its lush flowering will be a worthy reward for your efforts.
