Sorbus americana Marsh. American Mountain Ash. Native to eastern N. America, cultivated there and sometimes in Europe for attractive fruit and autumn colour. The fruit has a sharp flavour, is rich in vitamins and has been used in herbal remedies. Height to about 9m (30ft), often low and shrubby. Flowers open in May, about 0.3cm (¨ûin) across in flat clusters 7.5-10cm (3-4in) across. Fruit are about 0.6 (¨ùin). Leaves have 11-17 leaflets, on a dark red or green stem, and colour bright yellow in autumn. Z2.