Sorbus or uncertain parentage, have gained the Royal Horticultural Society’s Award of Garden Merit: Sorbus Sorbus is a genus of about 100–200 species of trees and shrubs in the rose family, Rosaceae. Species of "Sorbus" ("s.l.") are commonly known as whitebeam, rowan, service tree, and mountain-ash. The exact number of species is disputed depending on the circumscription of the genus, and also due to the number of apomictic microspecies, which some treat as distinct species, but others group in a smaller number of variable species. Recent treatments treat "Sorbus" in a narrower sense to include only the pinnate leaved species of
Sorbus decora Sorbus decora Sorbus decora, commonly known as the northern mountain ash, showy mountain-ash, or dogberry, is a deciduous shrub or very small tree native to northeastern North America. It occurs throughout the Laurentian Mixed Forest Province, the New England-Acadian forest region, and the eastern Canadian boreal forests. Showy mountain-ash grows tall. Its leaves are odd-pinnately compound, with 11–17 leaflets. Each leaflet is long and wide. All parts are hairless to slightly hairy. Flowers are borne in 125- to more than 400-flowered panicles across. Each flower is across and has five white petals long, 14–20 stamens, and carpels with 3–4 styles.