Description and characteristics of the Helsinki variety rhododendron university, planting and care
Among the existing varieties of rhododendrons, the Helsinki University variety stands out due to its ability to withstand temperature drops of up 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 color during the season.
Description and characteristics
An evergreen variety of rhododendrons Helsinki University is distinguished by the following features:
- bush height - 1.7 meters;
- crown width - 1.5 meters;
- funnel-shaped flowers of a light pink hue;
- leaf length - 12-14 centimeters;
- inflorescences are formed from 12-18 large flowers up to 8 centimeters in diameter.
The flowering of rhododendrons varieties Helsinki University begins in mid-June and ends with the onset of July.
Casting plants with a glossy surface in the spring have a reddish hue, which eventually changes to a dark green. The shrub has a dense and branched crown that can take regular shapes. The plant grows exclusively in loose and acidic soils, in shaded areas.
History of origin
This variety, named after the University of Helsinki, was officially registered in the relevant registers in the 70s of the last century. This type of shrub appeared by hybridization of short-fruited rhododendrons.
Features of the variety
The main feature of the University of Helsinki rhododendrons is that the plant tolerates temperature drops of up to -40 degrees. This ability is not observed in other types of culture. Also, this variety of shrub is able to withstand sudden changes in temperature, and does not rot in high humidity conditions.
Subsort Helsinki university
Each sub-variety of Helsinki University rhododendrons retained the main features of the parent plant, including the ability to bloom profusely after a long winter.
Hague
The sub-variety The Hague differs from the parent plant in that the flowers have a deep pink tint. The rest of the shrub is similar to the University of Helsinki rhododendrons.
Pink
This sub-variety stands out due to 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 due to a small bush, the height of which does not exceed one meter, and bright red buds and bell-shaped flowers.
Flowering features
The demand for rhododendrons, including the University of Helsinki varieties, among gardeners is explained by the fact that the shrub is able to bloom for a long time and beautifully, without requiring special care for itself.
When and how?
Flowers on the bushes of Helsinki University rhododendrons appear in early or mid-July and fall off after 3 weeks. After that, young shoots are formed on the bush. Flowers form at the tip of the branches.
What should 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 bud setting and budding should not exceed 15 degrees. After the petals fall off, gardeners recommend removing the remaining flowers.
What if it doesn’t dissolve?
Lack of flowering indicates insufficient feeding (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
The University of Helsinki recommends planting rhododendrons near:
- thuja;
- juniper;
- deciduous or coniferous trees.
The shrub grows well in the shade of large plants. Also rhododendrons are recommended to be planted in the vicinity of ornamental crops.
Landing
The planting of shrubs of the Helsinki University variety is carried out according to the same algorithm that is used when transferring seedlings of other rhododendrons to the open ground.
Seat selection
It is recommended to plant rhododendrons in shaded areas: next to trees or near the northern wall of the house. Prolonged contact with direct sunlight has a detrimental effect on the shrub.
Soil requirements
Rhododendrons prefer loose and acidic soils. Before planting a crop, it is recommended to add a mixture of leafy earth, 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 fertilizing. During the season, it is impossible to weed the shrub, since the plant's root system is close to the soil surface.
Pit preparation and planting scheme
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 pit can be enlarged if the bush has a branched root system.
A 20-centimeter drainage layer should be poured at the bottom of the hole, using a mixture of broken brick and river sand, and a previously prepared mixture of peat and leaf earth. Then you need to make a hole in the soil and insert the seedling so that the root collar remains at the soil level. At the end of planting, the plant is rammed, watered abundantly with clean water and mulched with peat and needles, a layer of up to six centimeters.
If more than one shrub is planned on the site, then the holes for seedlings should be placed at a distance of more than two meters.
Care
Rhododendrons varieties Helsinki University are not demanding in terms of care. The plant must be watered regularly, avoiding waterlogging, and fed several times per season.
Watering
It is necessary to water the bush up to three times a week, bringing under the bush up to 10 liters of rain or settled water (with a low calcium content). On cooler days, the procedure is carried out less frequently.Also, during the summer, you need to spray the leaves every day.
Top dressing
In the spring, a mixture of potassium, ammonium and superphosphate, taken in a 1: 2: 1 ratio (for each bush - no more than 30 grams), should be applied under the bush. After flowering, the plant is fed with phosphorus and potassium (2: 1).
Pruning
In the first season after planting the seedlings, it is recommended to remove all the buds. This will ensure better rooting. In the future, it is necessary to cut off damaged or old shoots by a third.
Preparing for winter
Due to its good frost resistance, the plant does not require serious preparation for winter.
Watering
The last time the bush is watered immediately after the onset of cold weather. This procedure is carried out to harden the plant.
Top dressing
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 a shelter
The Helsinki University variety is frost-resistant, therefore, the shrub is not covered for the winter.
Protection against diseases and pests
Slugs often appear on rhododendrons, which must be removed manually. When scutes 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
The shrub is transplanted in the spring, laying a mixture of sand, sawdust and peat in the prepared hole (proportion 1: 1: 2). To root the plant, add 40 grams of sulfur to the soil.
Reproduction
Rhododendrons reproduce 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 the planting material is covered with a film until the first shoots appear and left in a well-lit room at temperatures up to 20 degrees.
Cuttings
From an adult plant, you need to cut off branches 6-7 centimeters long. The cuttings are then placed in a mixture of peat and sand and covered with a jar. Within 3-4 months, the rooting of the bushes occurs, provided that sufficient watering is ensured.
Layers
To get a new bush, it is enough to bend the lower shoot to the ground, cut at the contact point and sprinkle it with earth. The next spring, a new shrub is replanted to a new location.
Prevention of various problems
The Helsinki University variety does not tolerate abundant moisture, slightly acidic soils and prolonged droughts. In order to prevent diseases, it is recommended to provide sufficient, but not excessive, watering and regularly apply top dressing. If dry leaves appear on the bush, then iron chelate should be added under the trunk.
For the prevention of diseases, the plant is treated in the fall with Bordeaux liquid.
Reviews
Anna, Petrozavodsk:
“The Helsinki University variety is one of the few beautiful plants that have taken root on the site near Petrozavodsk. The shrub tolerates local cold winters well even without shelter. "
Valentin, Leningrad region:
“In the first two seasons I regularly faced 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 anymore. "
