Rhododendron Helsinki University: variety description, planting and care, reviews with photos
Among the existing varieties of rhododendrons, the Helsinki University variety stands out due to its ability to tolerate temperature drops to -40 degrees. In addition, the culture is distinguished by lush flowering when growing in the northern regions and a dense crown, the width of which reaches 1.5 meters. And the large leaves of rhododendrons change colors during the season.
Description and characteristics
Evergreen variety of rhododendron Helsinki University has the following features:
- bush height - 1.7 meters;
- crown width - 1.5 meters;
- funnel-shaped flowers in light pink;
- leaf length - 12-14 centimeters;
- inflorescences are formed from 12-18 large flowers up to 8 centimeters in diameter.
Helsinki University rhododendron bloom starts in mid-June and ends with the onset of July.
Casting plants with a glossy surface in the spring have a reddish tint, which eventually changes to dark green. The shrub is distinguished by a dense and branched crown, capable of taking the correct forms. The plant grows exclusively in loose and acidic soils, in shady areas.
History of occurrence
This variety, named after the University of Helsinki, was officially registered in the relevant registries in the 70s of the last century. This variety of shrub appeared by hybridization of short-fruited rhododendrons.
Features of the variety
The main feature of the Helsinki University rhododendrons is that the plant tolerates a temperature drop of up to -40 degrees. This ability is not observed in other types of culture. Also, this variety of shrubs is able to tolerate sudden changes in temperature, and does not rot in conditions of high humidity.
Sub-grades of Helsinki university
Each sub-variety of Helsinki university rhododendrons retained the main features from the parent plant, including the ability to bloom profusely after a long winter.
The Hague
The Hague subvariety differs from the parent plant in that the flowers have a rich pink hue. The rest of the shrub looks like the rhododendrons of Helsinki University.
Pink
This sub-variety is distinguished by a large bush, the height of which reaches 2.5 meters, and long flowering (up to 1.5 months). The pink variety of rhododendrons has a pleasant aroma. The flowers are compact, no more than three centimeters in diameter.
Red
This sub-variety stands out with a small shrub that does not exceed one meter in height, and bright red buds and bell-shaped flowers.
Features of flowering
The demand for rhododendrons, including the Helsinki University variety, among gardeners is explained by the fact that the shrub is able to bloom for a long time and beautifully, without requiring special care.
When and how?
The flowers on the Helsinki University rhododendron bushes appear in early or mid-July and fall off after 3 weeks. After that, young shoots form on the shrub. Flowers form at the tip of the branches.
What must be observed?
Due to the fact that the plant spends a lot of energy during flowering, during this period it is necessary to provide abundant watering and good lighting. The air temperature during the laying of the kidneys and budding should not exceed 15 degrees. After the petals fall, gardeners recommend removing the remaining flowers.
What if it doesn't bloom?
Lack of flowering is indicative of undernutrition (micronutrient deficiency) or disease. To avoid such problems, it is recommended to periodically spray the foliage or water the shrub with cold water in the summer.
Use in garden design
Rhododendron varieties Helsinki University recommend planting next to:
- thuja;
- juniper;
- deciduous or coniferous trees.
Shrub grows well in the shade of large plants. Rhododendrons are also recommended to be planted next to ornamental crops.
Landing
Planting a shrub of the Helsinki University variety is carried out according to the same algorithm that is used when transferring seedlings of other rhododendrons to open ground.
Choosing a seat
Rhododendrons are recommended to be planted in shady places: next to trees or near the northern wall of the house. Prolonged contact with direct sunlight is detrimental to the bush.
Soil Requirements
Rhododendrons prefer loose and acidic soils. Before planting a crop, it is recommended to add a mixture of leafy soil, needles and peat to the soil in a ratio of 3: 1: 2. It is also necessary to organize a drainage layer in the hole and add mineral top dressing.During the season, it is impossible to weed the bushes, since the plant's root system is close to the soil surface.
Pit preparation and planting pattern
Rhododendron seedlings of the Helsinki University variety are recommended to be planted in holes 40 centimeters deep and at least 60 centimeters wide. If necessary, the hole can be enlarged if the bush has a branched root system.
At the bottom of the hole, a 20-centimeter drainage layer should be poured, using a mixture of broken bricks and river sand, and a mixture of peat and leafy soil prepared in advance. Then you need to make a hole in the soil and insert the seedling so that the root neck remains at the level of the soil. At the end of planting, the plant is rammed, watered abundantly with clean water and mulched with peat and needles, up to six centimeters thick.
If it is planned to plant more than one shrub on the site, then the holes for seedlings should be placed at a distance of more than two meters.
Care
Rhododendron varieties of Helsinki University are not demanding in terms of care. The plant must be watered regularly, avoiding waterlogging, and fed several times a season.
Irrigation
It is necessary to water the shrub up to three times a week, bringing up to 10 liters of rain or settled water (with a low calcium content) under the bush. On cool days, the procedure is carried out less frequently. Also during the summer you need to spray the leaves every day.
Feeding
In the spring, a mixture of potassium, ammonium and superphosphate, taken in a ratio of 1:2:1, should be applied under the bush (for each bush - no more than 30 grams). After flowering, the plant is fed with phosphorus and potassium (2: 1).
Cutting
In the first season after planting seedlings, it is recommended to remove all buds. This will provide better rooting. In the future, it is necessary to cut off damaged or old shoots by a third.
Preparing for winter
Due to good frost resistance, the plant does not require serious preparation for winter.
Irrigation
The last time the bush is watered immediately after the onset of cold weather. This procedure is carried out to harden the plant.
Feeding
Fertilizers under the bush are applied for the last time before the beginning of autumn. This is explained by the fact that top dressing stimulates the growth of shoots, the development of which interferes with preparation for winter.
Mulching
After the last watering, the soil around the trunk of the rhododendron is mulched using a mixture of peat and pine needles.
Preparing shelter
Helsinki University variety is frost-resistant, so the shrub is not covered for the winter.
Protection from diseases and pests
Slugs often appear on rhododendrons, which must be removed manually. When scale insects and spider mites appear, the shrub is treated with fungicides, and the weevil with Diazolin solution.
Due to abundant watering, the root system of the plant rots or fungal diseases develop. In such cases, it is recommended to remove the affected parts of the bush.
Transfer
Shrubs are transplanted in the spring, laying a mixture of sand, sawdust and peat in the prepared hole (proportion 1:1:2). To root the plant, 40 grams of sulfur are added to the soil.
Reproduction
Rhododendrons are propagated by seeds, cuttings and layering. The first option is rarely used.
Seeds
Seeds collected in August or September are sown in a mixture of peat and sand (3:1). The container with planting material is covered with a film until the first shoots appear and left in a well-lit room at a temperature of up to 20 degrees.
Shanks
From an adult plant, you need to cut branches 6-7 centimeters long. The cuttings are then placed in a mixture of peat and sand and covered with a jar. Bushes take root within 3-4 months, provided sufficient watering is provided.
Layers
To get a new bush, just bend the lower shoot to the ground, cut at the point of contact and sprinkle with earth. The following spring, a new shrub is transplanted to a new location.
Prevention of various problems
Helsinki University variety does not tolerate abundant moisture, slightly acidic soils and prolonged droughts. In order to prevent diseases, it is recommended to ensure sufficient, but not excessive, watering and regular top dressing. If dry leaves appear on the bush, then iron chelate should be added under the trunk.
To prevent diseases, the plant is treated with Bordeaux mixture in autumn.
Reviews
Anna, Petrozavodsk:
“Helsinki university variety is one of the few beautiful plants that have taken root in the area near Petrozavodsk. The shrub tolerates local cold winters well even without shelter.”
Valentin, Leningrad region:
“In the first two seasons, I regularly encountered fungal diseases, until I realized that I needed to reduce watering. Also every year I treat the shrub with antifungal mixtures. There were no other problems with this plant.”
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