The German Dendrological Society (Deutsche Dendrologische Gesellschaft) presented Arboretum Mustila with a batch of 3-year-old Nikko fir seedlings when they visited Mustila in 1925. A. F. Tigerstedt was somewhat sceptical regarding their success, but they are still growing today, along the road between Onnela and Hannula – quite successfully, though not particularly large.
Mustila’s Alppiruusulaakso (Rhododendron Valley) provides a hint of the feeling in a true beech forest. In the Valley’s warm rich soil and protected by other trees there is a single large beech and a couple of younger trees in much better condition than the specimens on Etelärinne (Southern slope), where they freeze down to snow level in cold winters.
On Etelärinne (Southern Slope) at Mustila, a large old cucumber tree which had survived even the cold winters of the 1940s, was finally destroyed in the 1970s by a combination of midsummer frost, dry summer, and an early cold winter. Only the stump was left, but from it sprouted a shoot, which has again grown to flowering size. The pale green blooms appear around Midsummer (about 21-22 June), and are easy to miss among the foliage. The showiness of the species does not lie in the flowers, but rather in the luxuriant general appearance and the large leaves, which can reach 20 cms.
Wild currant opens its foliage early and the flowers pass almost unnoticed. The tasteless berries are red, the autumn colour varies from orange to wine-red.
Wild currant is a useful ground-cover plant due to its prostrate habit. It is completely hardy and suitable for use on slopes and in rock gardens in a variety of conditions. The self-rooting of the branches when they are in contact with the soil helps it to spread. At Mustila, wild currant grows along the ditch that flows into the Oak Forest, under the red maples.
Common spindle is a deciduous, monoecious (i.e. male and female flowers on the same plant) species native to Europe, with only a wedge-shaped extension to its range extending into Asia, beyond the Caspian Sea.
The spindle’s flowers draw little attention but in autumn the fruit are much more attractive. They open into four red sections with dangling orange-coated seeds. In open situations the autumn colours, in shades of red, can also be impressive. There are several varieties available, whose fruits vary from white to crimson.
Sea buckthorn has an attractive shape and can easily be identified by its leaves, which are linear in shape, grey-green above and silvery below. The bud scales and young shoots have shield-like starry hairs. This is a pioneer shrub and does not tolerate shade; but it does tolerate direct sunlight, wind, flood and even salt. It is widespread throughout Europe and western Asia, though sufficiently open areas are rare.
American hornbeam occurs naturally over a large area in eastern North America. It thrives in shade and often grows in the forest under a canopy of larger species, on moist lake shores and river banks. It grows as a multi-stemmed shrub or small tree with an attractive crown. The dark grey, smooth and shiny bark emphasises the ridges of the trunk, which look like tensed muscles under the bark.
This species grows as a shrub along the west coast of North America from Alaska to New Mexico. Further inland it is very much a species of the Rocky Mountains, though its range also extends to the eastern valleys of the Cascades. It particularly favours the lower forested slopes of foothills.
The Ice Ages dealt severely with Finland’s flora, as they did on the other side of the world, in Japan. A variable group of evergreen rhododendrons can be found in the Japanese mountains which are believed to have survived the Ice Ages in warm coastal refuges. These relicts spread again as the ice sheets withdrew, and finally survived only in the mountains as the climate became too warm for them elsewhere. These changes are suggested as the reason for the variability nowadays of the species Rhododendron degronianum, with its different shapes of leaf, flower, and habit.
The woodland peony is an elvish woodland plant that has quite different attractions than the familiar garden peonies: the foliage consisting of rounded ovate leaflets are arranged in graceful whorls and above them the cup-shaped flowers are flaming either in white or rosy pink, depending of provenance.