Sorbus americana

RHS Plant Profile
American mountain ash

Other common names

roundwood

Synonyms

Pyrus americanus

Trees

A fairly slow-growing tree with a rounded crown and light green leaves comprising up to 15 leaflets, turning red or yellow in autumn. In late spring and early summer produces dense, flattened clusters of small white flowers, followed by orange-red berries

Position

Full sun, Partial shade

Soil Types

Clay, Loam, Sand

Max Height

8-12 metres

Max Spread

4-8 metres

Size

Time to Maturity
20–50 years
Max Spread
4-8 metres
Max Height
8-12 metres

Growing Conditions

Clay Loam Sand
Moisture
Moist but well–drained or Well–drained
pH
Acid or Neutral

Position

Full sun Partial shade
Aspect
South–facing or East–facing or West–facing
Exposure
Exposed or Sheltered
Hardiness
H6

Colour & Scent

Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Rosaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Spreading branched
Potentially harmful
Fruit are ornamentalnot to be eaten. Wear gloves and other protective equipment when handling. Pets: Fruit are ornamentalnot to be eaten - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus
Sorbus can be deciduous trees or shrubs with simple or pinnate leaves and clusters of small white or pink flowers, followed by white, yellow, pink, red or brown berries; some have fine autumn colour
Name Status
Correct
Plant Range
Eastern N America

How to Grow

Cultivation

Prefers moist but well-drained, acid or neutral soil in full sun or light, dappled shade

Propagation

Propagate by seed sown in containers in a cold frame in autumn or by taking semi-ripe cuttings in early summer

Suggested planting locations and garden types

  • City and courtyard gardens
  • Cottage and informal garden
  • Wildlife gardens
  • Low Maintenance

Pruning

Pruning group 1

Pests

May be susceptible to aphids, scale insects, pear blister mite, red spider mite and sawfly larvae

Diseases

May be susceptible to fireblight, apple canker, silver leaf and honey fungus