English walnut

Sun

Full sun; choose a sheltered position away from frost pockets.

Water

Water young trees deeply during dry spells. Established trees tolerate some drought, but prolonged dryness reduces nut size and cropping.

Soil

Deep, fertile, well-drained loam, preferably neutral to slightly alkaline. Avoid shallow soil, compacted ground and sites that remain waterlogged.

Height

40-80 ft (12-24 m)

Spread

40-70 ft (12-21 m)

Flowers

Spring: hanging yellow-green male catkins and small green female flowers appear as the leaves unfold.

Foliage

Large, aromatic leaves divided into usually 5-9 broad leaflets; green in summer, turning yellow or brown before falling.

Growth

Moderate; faster on deep soil with adequate moisture.

Care needed

Medium

• Drought tolerant
• Heat tolerant
• Wildlife
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2.2 m)

2. After 1 year

   10 ft (3.2 m)

3. After 2 years

   14 ft (4.1 m)

4. After 3 years

   17 ft (5.1 m)

5. After 5 years

   23 ft (7.1 m)

About 16 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Growth rate

Fast

• Plant while dormant, keeping the root flare at soil level and any graft union above the soil.
• Water deeply through the first two growing seasons whenever the root zone begins to dry.
• Keep grass away from the trunk and apply 2-3 in (5-8 cm) of organic mulch, leaving the bark clear.
• Stake only if needed on an exposed site, and remove the support once the tree is firmly rooted.
• Feed in spring only where growth or a soil test indicates a shortage; avoid heavy nitrogen feeding.
• For more reliable crops, choose locally suitable grafted trees with overlapping pollen-shedding and female flowering periods.

Pruning. Train young trees to a strong central leader with well-spaced branches, making small cuts in late summer when sap bleeding is less likely. Mature trees need little pruning; avoid topping or removing large limbs, and use a qualified arborist for substantial work.

Gather nuts in autumn when their green husks split and the nuts fall freely; collect promptly, remove the husks with gloves and dry the shells in a well-ventilated, squirrel-proof place. Grafted trees commonly produce a worthwhile crop about 4-7 years after planting, while seedlings often take 10-15 years or longer.

Late autumn

Plant dormant trees where soil remains workable and well drained; in very cold regions, wait until spring.

Early spring

Check ties, renew mulch and feed only if needed.

Spring

Watch for frost damage to new growth and flowers; record flowering times when planning a pollination partner.

Summer

Water young trees and bearing trees during prolonged dry weather.

Late summer

Carry out light formative pruning in dry weather.

Autumn

Collect fallen nuts frequently, remove husks and dry thoroughly before storage.

Late autumn

Remove diseased fallen leaves, husks and leftover nuts to reduce carry-over of pests and disease.

• Use as a specimen shade tree in a large lawn, well away from buildings and paved seating areas.
• Plant in a spacious nut orchard with compatible flowering partners and room for harvesting.
• Place at the edge of a productive garden, keeping sun-loving vegetables beyond its eventual canopy.
• Use its broad crown as a long-term landscape feature in a country or estate garden.

Garden styles it suits: Backyard orchard, Edible landscape, Homestead, Grand estate, English country and Food forest.

Plant it with: Daffodils, Hostas, Daylilies and Elderberry.

Wildlife: Nuts feed squirrels, rodents and some birds, while mature trees provide nesting sites and shelter. Flowers are wind-pollinated rather than a significant nectar source for bees.

• Walnut blight: blackened young nuts, shoots and leaves are worse in wet springs. Choose locally resistant cultivars, avoid overhead watering and remove infected debris; seek local advice before using any registered treatment.
• Walnut leaf blotch or anthracnose: brown leaf spots and early leaf fall can weaken trees. Collect affected fallen leaves and maintain an open crown through light pruning.
• Codling moth: larvae can enter developing nuts in affected regions. Remove damaged nuts promptly and use locally recommended monitoring and control timed to moth activity.
• Poor cropping: late frost, insufficient summer warmth or poor overlap between male and female flowering can limit yields. Choose locally proven, late-leafing cultivars and a suitable pollination partner.

Ripe, sound kernels are edible to people, but walnut allergy can be severe. Green husks and sap can stain and irritate skin. Mouldy nuts and husks can cause serious poisoning, including tremors and seizures, in dogs and potentially other pets; keep cats and dogs away from fallen, decaying nuts. English walnut is not established as causing the same horse-bedding toxicity as black walnut, but keep horses away from walnut wood shavings and mouldy nuts.

• Black walnut (Juglans nigra)

  Usually has 15-23 narrower, toothed leaflets, often with a small or missing terminal leaflet; its nuts have very thick, deeply ridged shells.

• Butternut (Juglans cinerea)

  Has more numerous, toothed leaflets and sticky, hairy, elongated fruits rather than the English walnut's rounded fruits.

• Japanese walnut (Juglans ailantifolia)

  Has much larger leaves with numerous toothed, hairy leaflets and fruits commonly borne in conspicuous clusters.

Juglans comes from Latin words meaning 'Jupiter's nut', and regia means 'royal'; the name English walnut reflects its historical trade through England rather than its native origin.

Propagation. Named nut cultivars are propagated by grafting or budding onto suitable walnut rootstocks. Fresh seed can be cold-stratified and sown, but seedlings vary in nut quality, grow large and take much longer to crop.

Accepted botanical name

Juglans regia

In the US and Canada

Introduced in Canada and the lower 48 states.

Native range

Afghanistan, Iran, Iraq, Lebanon-Syria, North Caucasus, Pakistan, Transcaucasus, Turkey and West Himalaya.

Measured

Soil pH 6 to 7.5. Average height 1400 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.