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 damp, acidic, low on nutrients, sandy, and loose. It often grows in stony soil or clay soil, but also sandy soil or wet peat. The plant grows best on fresh, loose, and fertile soil, prefers average humidity, and does not tolerate saline soil or waterlogging. It can be found in light woodland of all kinds and as a pioneer species over fallen dead trees or in clearcuttings, and at the edge of forests or at the sides of roads. Seeds of "S. aucuparia" germinate easily, so the plant may appear on inaccessible rock, ruins, branch forks, or on hollow trees.