Mountainash, European - - Sorbus aucuparia
A member of the rose family, the European mountainash grows best in northern climates. Its habit is erect and oval in youth and symmetrical, oval or vase-like at maturity. It is often low-branched or multi-stemmed. The bark is smooth, shiny, gray brown with visible horizontal lenticels becoming slightly roughened on older trees. The clusters of creamy white flowers appear in the spring after the leaves mature. The dark green compound leaves are composed of 9-15 oblong to lanceolate leaflets with serrated margins on the upper half of the leaflet. In late summer or early fall the heavy clusters of small, bright, orange-red berry-like fruits ripen. Birds eat the fruit, and it often does not persist on the tree into winter. Fall leaf color ranges from green to yellow, red, or reddish purple. European mountainash prefers acid, moist, well-drained soils and is intolerant of alkaline or compacted soils, polluted atmospheres, and high summer heat. Because these trees are sensitive to a variety of insect and disease problems, it is important to keep them free of stress. This species requires pruning to develop a strong branch structure.