There are lots of wild asters in North America. Blue wood aster is common on wooded East-coast slopes and tolerates shade better than most of its relatives. Blue wood asters have been planted at Mustila where they thrive in the shade of the Rock (Sugar) Maples (Acer saccharum) south of the Festival Area. The large, heart-shaped leaves effectively cover the ground, and in late summer blue wood aster puts out tall stems with big blue florets.
American elm has the largest range of any of the six elm species growing in North America, covering the whole of the eastern parts of the continent west to the Rocky Mountains, but omitting the mountainous areas, high plateaus and the coldest conifer zone. It thrives best in moist valleys and flood meadows, but is quite happy when planted on drier soils.
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.
American elder closely resembles the European species, common elder (S. nigra), and is sometimes considered its subspecies. It is a fast-growing, luxuriant, multi-stemmed shrub producing root suckers, unlike the common elder. Leaves are large, with 5-9 leaflets, giving the shrub an exotic look. American elder flowers in August, after the common elder, with white, scented corymbs. The blue-black berries seldom have time to ripen in Finland. There is conflicting information about their edibility.
American basswood is native to the north-eastern United States and southern Canada, though in cultivation it can grow even further north. In the wild it prefers dry or somewhat moist, normal to rich soil in broadleaf or mixed forest, but also occurs on rocky ground.
Stag’s horn sumach is native to the north-eastern parts of North America. It is a suckering tree or shrub which thrives in full sun, on sandy slopes or along roadsides.
The attractive leaves are composed of multiple leaflets, which in autumn take on all possible shades of yellow, orange, red and violet. In summer it bears small green flowers in erect cones, 20cms, which in the females change in autumn to handsome glowing red spikes of berries coated in red hairs, which remain on the tree after the leaves fall.
The leaves of the red oak are larger, and the lobes more pointed, than those of the native oak (Quercus robur). Their strong red autumn colour dominates the landscape in their native range, the eastern parts of North America, but in Finland they aren’t usually as strongly coloured, usually a brownish red.
The American hop hornbeam is a small tree of the forest edge, with beautiful foliage. Its range is enormous, from the mountains of Guatemala and Honduras in the south to the northern limit of the deciduous tree belt in Canada, in Manitoba, Ontario and Quebec. It was brought to Mustila from seed collecting trips to these Canadian provinces in 1993 and 1996.
This clematis is common in the forests, roadsides and riverbanks of the eastern parts of North America. It climbs up trees, grows over bushes and fences or – if it has nothing to cling on to – along the ground.