Juglans sigillata

RHS Plant Profile
iron walnut
Trees

A broad deciduous tree reaching 25m tall by 15m wide. The leaves emerge copper-coloured then become bright green then yellow before they fall. They are very large (up to 50cm long) and have usually 9 or 11 pointed leaflets which are fragranced when bruised. The flowers are insignificant but turn into green fruit in late summer from which edible walnuts can be extracted.

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

Higher than 12 metres

Max Spread

wider than 8 metres

Size

Time to Maturity
20–50 years
Max Spread
wider than 8 metres
Max Height
Higher than 12 metres

Growing Conditions

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

Position

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

Colour & Scent

Fragrance Foliage
Season Stem Flower Foliage Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family
Juglandaceae
Native to GB/Ireland
No
Foliage
Deciduous
Habit
Spreading branched
Genus
Juglans are deciduous trees with pinnate leaves, and inconspicuous flowers in catkins followed by usually edible nuts
Name Status
Correct

How to Grow

Cultivation

Grow in any deep, fertile soil. Suited to very large gardens or parks. For nut production, more than one tree is needed for cross pollination

Propagation

Propagate by seed (for more advice see propagate from seed (tree/shrub)

Suggested planting locations and garden types

  • Architectural
  • Edible fruit

Pruning

Pruning group 1

Pests

May be susceptible to aphids and walnut blister mites

Diseases

May be susceptible to walnut leaf spot, walnut leaf blotch, honey fungus and coral spot