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Rhododendron brachycarpum

Rhododendron brachycarpum var. tigerstedtii - Mustila Rhododendron

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In 1931 Mustila Arboretum acquired some seeds of Rhododendron aureum from the Pungsan Mountains of North Korea. But the seedlings turned out to be something quite different: a previously poorly-known Korean form of the Japanese rhododendron (R. brachycarpum), a sturdy-growth variety with large leaves and flowers that in 1970 was named Rhododendron brachycarpum subsp. tigerstedtii and subsequently known in Finland as the Mustila Rhododendron.

The Mustila Rhododendron was the only rhododendron variety to survive the exceptionally cold winter of 1939–1940. Being unusually hardy, it provided a basis for the hybridisation programme begun at the University of Helsinki in 1973 using the hardy varieties already growing at Mustila and the Mustila Rhododendron as its main maternal parent. The resulting varieties have been on sale since 1990, but the Mustila Rhododendron itself is hardly produced anywhere commercially.

The original old Mustila Rhododendrons at the southern end of Rhododendron Valley are easy to spot by virtue of their size alone. The leaves are dark green, shiny and large, and they protect themselves from cold and drought by winding themselves into tight rolls even at temperatures only just below zero. The Mustila Rhododendron blossoms abundantly roughly once in three years. The flowers are like open bells, white with brown dotting, and break in the first half of June.

 

Rhododendron brachycarpum subsp. brachycarpum

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Rhododendron brachycarpum var. brachycarpum is an evergreen shrub, sometimes resembling a small tree in habit but only about 1-4m high. Its natural range covers central and northern Japan, including the Russian-administered island of Kunashiri. The robust and large-leafed form growing in Korea is sometimes considered a subspecies, sometimes a race, and is known in Finland as Mustila Rhododendron.

Because they are geographically isolated from each other, the various populations of this rhododendron show large variations. Those growing in Japan are usually smaller than those on the continent, and especially in full light are dense shrubs. The shiny leaves are smaller, 10-15 cm long, with thin reddish hairs on the undersides. The smallish white (sometimes with red) flowers are among the latest rhododendrons to open at Mustila, usually not till after mid-June.

As a mountain species, this rhododendron is adapted to cool summers and is hardy in cold winters. Because it begins growing early, the new growth is often damaged in places susceptible to spring frosts. Its multiplicity of habit can be observed at Mustila, where shrubs vary from low ground-cover to almost tree-like forms.

In Western literature, several subspecies are recognized, e.g. subsp. fauriei, whose leaf undersides are hairless. This form does not grow at Mustila, though several plants have been received under the Rhododendron fauriei name. This is due to the Asian naming system, in which Rhododendron brachycarpum and Rhododendron fauriei are synonyms and Rhododendron fauriei has priority, regardless of any – or no - hairiness.

 

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