Rhododendron 'Helsinki University'

The variety was obtained as a result of the program for breeding rhododendrons of the University of Helsinki in collaboration with the Arboretum Mustila (1973-2000). The program used rhododendrons growing in the Helsinki Arboretum since 1930. By 1973, the most winter-hardy survived from these plants. One such plant was Rhododendron brachycarpum subsp. tigerstedtii .

Initially, 53 mother plants and, as pollinators, representatives of 23 species and 48 rhododendron hybrids were used in the breeding program. Of the first 22,000 hybrid seedlings received, 14,000 were selected. As a result of the harsh winters of the 1980s, 9,000 out of 14,000 seedlings survived. Among the survivors, there were many plants that were completely undamaged during the winter. Of these, 80 seedlings were selected, which were propagated by microclonal propagation . Nine varieties have been reported ^[2] :

• 'Elviira'
• 'Hellikki'
• 'Haaga'
• 'Helsinki University'
• 'Kullervo'
• 'Pekka'
• 'Peter Tigerstedt'
• 'Pohjola's Daughter'
• 'Mikkeli'

A plant belonging to one of the subspecies of the rhododendron short-fruited - Rhododendron brachycarpum subsp. Was used as the mother plant for obtaining the Helsinki University variety. tigerstedtii . The second parent is not exactly known because the fingers of various rhododendrons were used to obtain the seeds from which the control lot of seedlings was grown (from which the plant was later selected for microclonal propagation) ^[3] .

Rhododendron 'Helsinki University' is used as an ornamental garden plant . Named in honor of the 350th anniversary of the University of Helsinki , celebrated in 1990 ^[3] .

At the age of 10 years, the height of the plant is about 1.5 m ^[4] , according to another source of 100 × 100 cm ^[5] . The height of an adult plant is up to 2 m ^[3] .

Leaves are bare, dark green, 110-150 × 55 mm ^[5] .

Inflorescences are located at the ends of shoots, conical, 120 mm high, 130 mm wide, bear 12-18 flowers ^[5] .

Flowers with a diameter of 76 mm, pink with red spots on the inside, 6 petal.

The variety is characterized by good flowering even after severe winters ^[4] .

In the south of Finland it blooms in mid-June, in the north later ^[3] .

'Helsinki University' strongly resembles the sort of 'Haaga'. The easiest way to distinguish varieties is by the color of the buds: at 'Haaga' they are more reddish. In addition, the stamens of the 'Haaga' flowers are pink, while at the 'Helsinki University' they are lighter ^[6] .

It withstands temperature drops to -32 ^[5] ... −39 ° C ^[4] .

Location: partial shade or variegated shadow of a sparse pine forest.

The soil is water-intensive, well aerated, acidic ( pH from 4.5 to 6.5). Since plants have a superficial root system, they need to be watered in dry periods. To maintain soil moisture, it is recommended to use mulching . Fertilizing is recommended from May. Since June, nitrogen-containing fertilizers are excluded.

The recommended distance between plants is 1.5 meters.

To protect against winter drying out of leaves, it is recommended to build a breathable shelter from burlap ^[3] .

It blooms simultaneously with the growth of young shoots, which somewhat reduces decorativeness ^[7] .

• 'Orlando' , Hans Hachmann (1998) = ( R. 'Helsinki University' × Rhododendron rex )

• Anu Vanola. Genetic and physiological aspects of cold hard i ness in Rhododendron . - Academic dissertation in plant breeding. - University of Helsinki, 2000.

• Lecture by Voronina S. Rhododendrons. Difficult choice problem.
• James Kohut, Staff Writer. Growing Azaleas And Rhododendrons In The North . Northscaping.com. Date of treatment March 12, 2013. Archived March 16, 2013.