Rhododendron University of Helsinki is the most frost-resistant variety of the entire genus. It easily tolerates temperature changes and a sharp cooling. Feels good and blooms luxuriantly even after the most persistent frosts. But in landing and leaving there are some nuances that are described below.
History of occurrence
The history of the variety begins at the University of Helsinki, which at that time collaborated with the Arboretum Mustila. Variety cultivation lasted from 1973 to 2000. Only those specimens that were present in the Helsinki Arboretum and survived severe frosts from 1930 to 1973 were involved in breeding.
Initially, 53 plants of the short-fruited rhododendron subspecies were taken for breeding; 48 hybrid and 23 pure species were chosen for pollination. As a result of reproduction, 22 thousand seedlings were obtained, of which only 14 thousand copies were selected for further participation in the program. Severe frosts could not survive 5000 seedlings. Of these, the most persistent plants were again selected, of which only 80 were found. Then they were subjected to microchannel propagation. At that moment, nine new frost-resistant varieties were registered.
For your information! The variety was named in honor of the anniversary of the University of Helsinki. In 1990, he turned 350 years old. From that year, the bush began to be actively used as an ornamental plant to decorate garden plots.
Description and characteristic
The maximum height of the plant is 2 m, by 10 years the plant rises by 1-1.5 m. It has a spherical crown, the average diameter of which is 1-1.5 m. The leaves of the rhododendron are dark green, oblong, reaching a length of 15 cm. In each inflorescences are located on average 15 flowers. The buds are pink, six-petalled, inside have red spots.
Under natural conditions, in particular, in the south of Finland, the evergreen rhododendron blooms in mid-June, in the northern regions this period begins later. Even after suffering a cold winter, Helsinki's rhododendron will bloom again magnificently.
Note! The flower can be grown in almost all regions, because the maximum temperature that it can survive is −39 ° С.
Rhododendron University of Helsinki will not only decorate the local area, but also save the owners from ailments.
Therapeutic properties of the plant:
How to bloom
The composition of the leaves includes essential oils, tannins, ascorbic acid, rutin, arbutin, andromedotoxin, ericoline, volatile, etc.
Tea made from flowers will help with colds, diseases of the gastrointestinal tract, urolithiasis, and the fight against staphylococci and bronchial asthma.
Tincture of leaves and flowers can be rubbed with neuralgia, osteochondrosis, polyarthritis, sciatica, used for douching with cervical erosion.
Important! Rhododendron juice also contains poisonous substances, therefore it is contraindicated for pregnant and lactating women, people with kidney failure.
At the Helsinki University Garden Plot, rhododendron is used to decorate alpine paths and slides. It can be combined with any ornamental plants, looks good with juniper and arborvitae.
It grows better in the shade than in the sun. Creating a composition, it must be borne in mind that the crown of the bush is dark green.
In landscape design
Rhododendron Care and Growing
Planting and caring for the Helsinki Rhododendron University begins with choosing a good place. The soil must be acidic - pH from 4.5 to 6.5. Suitable porous, moisture-resistant soil. In hot weather, the Helsinki rhododendron requires frequent watering, since its root system is superficial. Mulching will help ease the task of wetting the soil. So that the roots do not interfere with each other's development, it is recommended that the bushes be grown at a distance of 1.5 m from each other.
Only young bushes of the University rhododendron need pruning. In the first year of life, all buds and damaged branches are cut from the plant. It is necessary that nutrients are more directed to the development of the root system.
In the future, pruning flowers and crowns can be omitted. The variety has the correct shape and does not need its artificial formation. To rejuvenate the bush, only the removal of old, dried shoots is practiced. It is allowed to remove no more than 25% of the total mass of the bush. Places of cuts of branches are processed by garden var.
You do not need to wait until the plant itself discards the wilted inflorescences, it is also better to cut them off immediately. This will help save energy on flowering next year.
Note! The Helsinki University hybrid rhododendron blooms lushly after a year.
Watering and feeding
Rhododendron University of Helsinki loves a lot of moisture, so in the heat of 1 bush you will need about 10 liters of water 3 times a week. Every day in the evening the plant is sprayed. In autumn and winter, watering is almost not required, only as the soil dries.
The water used for irrigation is soft, unsalted, acidified if possible.
For your information! Fertilization begins immediately after planting a shrub in the area. To increase the acidity of the soil, calcium, superphosphate and ammonium are added to the water.
In the spring, the plant is fed with potassium and phosphorus (1: 2). It is important not to overfeed young specimens, therefore fertilizers are made less concentrated in half.
Fertilizers with the content of potassium, magnesium and calcium are bred with a proportion of 1.2: 1000.
The fertilizer application is as follows:
- 50 g per 1 m² of magnesium sulfate and ammonium sulfate are introduced in early spring;
- 20 g of potassium sulfate and superphosphate, 40 g of ammonium sulfate are introduced in June;
- 20 g of potassium sulfate and superphosphate are added in July.
A good option is top dressing made from half-rotten cow manure, which is bred with water in a proportion of 1:15. Before applying fertilizer for several days should be infused.
In winter, plants are not dug up; they tolerate frosts well. However, to avoid drying out the leaves, the bushes are covered with burlap or other textile material that allows air to pass through.
How to shelter for the winter
In nature, the plant propagates by seeds, at home it is easier to use cuttings or cuttings.
Semi-lignified shoots are cut up to 8 cm long, the lower leaves are cut. The cutlery is placed in a vessel with a root growth stimulator for 16 hours. For rooting, use a mixture of peat with sand in a ratio of 3: 1. Cuttings are covered with a jar or a transparent film. The rooting period is from 1.5 to 4 months.
An easier and faster way is used directly on the land. For propagation by layering, a groove is pulled out near the maternal shrub, into which the middle part of the shoot is put and sprinkled with earth. The upper part of the branch is attached to an erect peg. When the branch takes root, it can be separated and transplanted to another place.
The place for growing rhododendron is chosen shaded, in nature it grows in a pine forest, which allows, but cuts through sunlight. Shrubs will feel good on the north side of the site.
Diseases and pests
The following parasites can infect rhododendron hybrid Helsinki University:
- spider mite;
- scale shield;
- rhododendron bug;
Slugs and snails are collected from the bush by hand, with other pests the situation is more complicated. Small insects die after the shoots are treated with fungicides, karbofos, but weevils can be dealt with using diazonin.
Note! Yellow leaves indicate a fungal disease that can be eliminated by adding iron chelate, copper sulfate or citric acid to water for irrigation.
Prevention of various problems
The best disease prophylaxis for Finnish rhododendron is to choose the right place and care for the plant. Rhododendron is more vulnerable if it grows in the sun, in alkaline soil, is oversaturated with moisture or fertilizers.
As a preventative measure, in late autumn, the shrub is treated with a solution of Bordeaux fluid.
Rhododendron is not a plant for the lazy. Only by providing him with special care, you can wait for the results. Lush flowering will not leave indifferent any grower.