About
Sorbus americana, the American mountain ash, is a fairly slow-growing, rounded-crown deciduous tree producing light-green, pinnate leaves of up to 15 leaflets turning red or yellow in autumn, dense, flattened clusters of small, white flowers in late spring and summer, and orange-red berries. A rewarding ornamental tree for a sunny, well-drained garden.
About the genus
Sorbus, the mountain ashes, rowans and whitebeams, are deciduous trees or shrubs producing simple or pinnate leaves and clusters of small, white or pink flowers followed by white, yellow, pink, red or brown berries; many provide excellent autumn colour. Rewarding and ornamental trees and shrubs for a sunny, well-drained garden.
Growing conditions
SunlightFull sun, Partial shade
Soil typeClay, Loam, Sand
Soil pHAcid, Neutral
Soil moistureMoist but well-drained, Well-drained
AspectSouth-facing, East-facing, West-facing
ExposureExposed, Sheltered
UK hardinessH6
Plant details
Plant typeTrees
HabitSpreading branched
FoliageDeciduous
Height8-12 metres
Spread4-8 metres
Time to full height20-50 years
Suggested usesCity and courtyard gardens, Cottage and informal garden, Wildlife gardens
Native toEastern N America
ToxicityFruit are ornamental, not to be eaten. Wear gloves and other protective equipment when handling. Pets: Fruit are ornamental, not to be eaten - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Care notes
CultivationPrefers moist but well-drained, acid or neutral soil in full sun or light, dappled shade
PruningPruning group 1
PropagationPropagate by seed sown in containers in a cold frame in autumn or by taking semi-ripe cuttings in early summer
Pest resistanceMay be susceptible to aphids, scale insects, pear blister mite, red spider mite and sawfly larvae
Disease resistanceMay be susceptible to fireblight, apple canker, silver leaf and honey fungus