Rowan Several of the Asian species are widely cultivated as ornamental trees. North American native species in the subgenus "Sorbus (Sorbus)" include the American mountain-ash "Sorbus americana" and Showy mountain-ash "Sorbus decora" in the east and Sitka mountain-ash "Sorbus sitchensis" in the west. Numerous hybrids, mostly behaving as true species reproducing by apomixis, occur between rowans and whitebeams; these are variably intermediate between their parents but generally more resemble whitebeams and are usually grouped with them (q.v.). Rowans are excellent small ornamental trees for parks, gardens and wildlife areas. Several of the Chinese species, such as White-fruited rowan ("Sorbus glabrescens") are
Sorbus aucuparia be applied to other species in "Sorbus" subgenus "Sorbus", and mountain ash may be used for several other distantly related trees. The species is unrelated to the true ash trees (genus "Fraxinus"), which also carry pinnate leaves or the species "Eucalyptus regnans", also called mountain ash, native to Tasmania and Victoria in southeastern Australia. "S. aucuparia" was previously categorized as "Pyrus aucuparia". The author citation "Sorbus aucuparia" L. belongs to Carl Linnaeus. "Sorbus aucuparia" occurs as a tree or shrub that grows up to between 5 and 15 m in height. The crown is loose and roundish or irregularly shaped