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 which is a hybrid with "Sorbus aria". The main pests for "S. aucuparia" are the apple fruit moth "Argyresthia conjugella" and the mountain-ash sawfly "Hoplocampa alpina". The rust fungus "Gymnosporangium cornutum" produces leaf galls. The leaves are not palatable to insects, but are used by insect larvae, including by the moth "Venusia cambrica", the case-bearer moth "Coleophora anatipennella", and leaf miners of the genus "Stigmella". The snail "Helix aspersa" feeds on the leaves. The plant can suffer from fire blight. Fossils of "Sorbus aucuparia" have been described from the fossil flora of Kızılcahamam district in Turkey, which is of early