Orange-/Vermillion-fruited Rowans
Rose family (Rosaceae)
Origin: Cooler parts of the N. Hemisphere
Members of the genus Sorbus are able to produce fertile seed via non-sexual reproduction, where seedlings are genetically identical to the parent i.e. clones. Many species will hybridise, and the hybrids are also able to produce clones. The result is numerous so-called ‘microspecies’ which are genetically distinct but resemble each other very closely in appearance.
A practical way of identifying these microspecies is to divide them into only two groups, based on their fruits. The first group contains all rowans with orange, vermillion, or occasionally yellow fruits.
Description:
Slender tree up to 20 m but usually much smaller. Crown open, with spreading branches. Leaves alternate, pinnate, with 5 to 10 pairs of leaflets. Leaflets 3-6 cm, oblong, toothed in the upper half, base unequal, grey hairy beneath. Flowers 8-10 mm across, white, in flat or slightly domes clusters. Fruits globose or ovoid, usually vermillion, also orange or yellow, always with yellow pulp.
Sorbus aucuparia is native to the UK and is the most commonly planted species.
Sorbus ‘Asplenifolia’ has bi-pinnate leaves (the leaflets are themselves pinnate). It is less frequently planted in streets than other rowans as it does grow well when its roots are under pavements.
Sorbus ‘Joseph Rock’ closely resembles S. aucuparia but has yellow fruits. It is one of the most commonly planted cultivars.
Sorbus commixta has smaller, ovoid fruits which ripen orange.
Comments:
Rowans are the pinnate-leaved species of Sorbus (the remaining species are whitebeams and service-trees). They are among the most distinctive of small trees, especially in flower or fruit. Most species produce bright autumn colours.
Similar trees:
These trees can be confused with elder (Sambucus nigra) but the foliage and flowers of elder have an unpleasant scent and elder berries are blue-black when ripe.
