General information: around 600 taxons
Area: 1.6 ha and many enclaves
The collection consists of two main parts: the Rhododendron and Azalea Collection (fot 1.) and the Ericarium Collection as well as several enclaves in different parts of the botanical garden. The collection includes 21 botanical genera of the Ericaceae family of heathers. This is a family of plants adapted to living in acidic soil or with acidifying agents with a pH of 3.5-6.0. The family includes about 4 000 species from all over the world that grow on all continents except Antarctica.
Rhododendron is the largest group of heathers in the botanical garden and is represented by around 400 taxons. One can also admire the following genera: Andromeda, Arctostaphylos, Bruckenthalia, Calluna, Chamaedaphne, Daboecia, Elliottia, Enkianthus, Erica, Gaultheria, Kalmia, Ledum, Leucothoë, Lyonia, Menziesia, Oxycoccus, Oxydendrum, Pieris, Rhododendron, Vaccinium, and Zenobia.
Collection of rhododendrons and azaleas
General information: around 400 taxons
Area: around 1.1 ha
The collection began to form in the 1980s and 1990s. Initially, varieties were collected in the so-called mother plant in the vicinity of the villa Janówek, where the oldest specimens can be found. Subsequently, collections were started in the Arboretum and Oak Avenue. The collection comprises 121 botanical species, 171 varieties of evergreen rhododendrons and 130 varieties of azaleas.
The yellow azalea (Rhododendron luteum Sweet.) (Photo 2), also known as Pontic azalea, is a species of this genus that grows in Poland. Its large groups are located at the northern entrance to the garden.
Some of the earliest species in the collection to flower is the dahurian rhododendron (Rhododendron dauricum L.) and its cousin Rhododendron ledebourii Pojark. (Photo 3) which can flower even in March. Some of the most beautifully flowering azaleas include the royal azalea (Rhododendron schlippenbachii Maxim.) (Photo 4) with its large fragrant flowers and Rhododendron albrechtii Maxim. with intensely coloured pink flowers.
Rhododendron degronianum ssp. yakushimanum is one of the more interesting specimens – a Japanese endemic species which grows only on the one small island of Yakushima and is the parent of cultivars found in gardens. The Alpine rhododendron (Rhododendron ferrugineum L.) (Photo 5) is shrouded in legend – it is said to have saved the life of Count Fritz von Oheimb during an Alpine excursion.
The collection’s crowning evergreen variety is the rhododendron ‘American’ (Photo 6), a large evergreen shrub with ruby red flowers. Spots with this variety can be found in every part of the collection. The ‘Catawbiense Album’ (Photo 7) variety boasts large white flowers. Sometimes famous or crowned figures, and sometimes family members of their discoverers, appear among the names of varieties, as is the case for ‘Kate Waterer’ (Photo 8) with its beautiful neon pink flowers. Two-coloured varieties, often combining contrasting colours, are popular with gardeners and breeders. One such variety that can be found in the collection is ‘Tamarindos’ (Photo 9) with its purple flowers and a large yellow blotch on the upper petal.
The varieties of azaleas clustered along one of the Arboretum’s fields are admired by our guests every year, with the beautiful colours, smells and combinations drawing crowds. The classic form of the ‘Tucan’ (Photo 10) variety, which has a white flower with a yellow blotch, is beautiful in appearance. Varieties with only one petal colour, such as ‘Eisprincessin’ (Photo 11), will also find their admirers. The Rustica group, introduced into cultivation back in the 19th century, is represented by the ‘Phebe’ (Photo 12) variety with its full flowers with sharp petal endings. ‘Carat’ (Photo 13) has been aptly named after its flowers resembling ruby gems. The variety is derived from the swamp azalea which can be found in the Ericarium.
General information: around 120 taxons
Area: 0.35 ha
The species collected over the years come from North America, Asia and Europe. The collection is situated in the eastern part of the Arboretum, between the Warsaw Escarpment and one of the numerous ravines. Surrounded by trees and densely overgrown, it creates an interesting display of light, colour, scent and texture at every time of the year.
The collection contains little-known and rare species of rhododendron (Rhododendron) as well as valuable garden varieties. Your attention might be drawn by the Rhododendron viscosum Torr. (Photo 14), with white star-shaped and strongly scented flowers, or the Canada rosebay (Rhododendron canadense (L.) Torr.) (Photo 15) with charming pink-purple flowers; both are native to North America. Among the representatives of the genus from Asia, one should look at the Makino rhododendron (Rhododendron makinoi Tagg) (Photo 16) with thin long leaves. The Korean azalea (Rhododendron yedoense var. poukhanense (Lévl.) Nakai) (Photo 17) is a pink gem. Its flowering is considered one of the most abundant among azaleas – in May, the shrub is covered with a profusion of pink, fragrant flowers.
Little-known representatives of the heathers worthy of a closer look are the American sourwood (Oxydendrum arboretum (L.) DC.) (Photo 18), a tree representative of the Ericaceae family with beautiful panicle flowers appearing in summer, and the dusty zenobia (Zenobia pulverulenta (W. Bartram ex Willd.) Pollard) (Photo 19) – a small shrub with flowers similar to lily of the valley, named after Zenobia, Queen of Palmyra. In winter, the collection is decorated by doghobble (Leucothoë fontanesiana (Steud.) Sleumer) (Photo 20) with evergreen leaves that turn red in the cold season, placed alternately on overhanging stems. The spring sees the flowering of redvein enkianthus (Enkianthus campanulatus (Miq.) G.Nicholson) – a shrub from the mountainous areas of Asia with beautifully coloured leaves in autumn. There are three species of the genus Pieris in the collection – shrubs with evergreen leaves similar to bay leaves and panicles of white bell-shaped flowers – mountain andromeda (Pieris floribunda (Pursh) Benth. & Hook. f.) (Photo 21), Japanese andromeda (Pieris japonica (Thunb.) D. Don ex G. Don ) and Himalayan andromeda (Pieris formosa (Wall.) D. Don). Elliottia bracteata Benth. & Hook is another curiosity hidden away in the collection – a small plant with white flowers with a patch of pink.