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Quick facts

Common name: walnut, common walnut, English walnut

Scientific name: Juglans regia

Family: Juglandaceae

Origin: non-native

Walnut is a deciduous broadleaf tree which can grow to 35m. They typically have a short trunk and broad crown, though can be narrower if grown in a woodland situation. The bark is smooth and olive-brown when young, developing fissures and fading to silver-grey with age. Twigs are stout, green and curving.

Look out for: crushed leaves that smell like polish.

Identified in winter by: the unsegmented inside pith, or spongy centre, of the twig. At their base, buds have horseshoe-shaped leaf scars, or marks, left by fallen leaves.

What does walnut look like?

Walnut leaves on tree

Credit: Marcus Harrison / Alamy Stock Photo

Leaves

Shiny and pinnate (feather-like), with 5–9 paired oval leaflets and one 'terminal' leaflet at the end.

Walnut flowers emerging

Credit: Marcus Harrison / Alamy Stock Photo

Flowers

Male flowers are drooping yellow-green catkins, 5–10 cm long, and the female flowers appear in clusters of 2–5.

Open fruits of walnut

Credit: Imagebroker / Alamy Stock Photo

Fruits

Pollinated by wind, female flowers develop into a fruit with a green, fleshy husk and a brown, wrinkled walnut.

Did you know?

The botanical name of the English walnut, Juglans regia, means the 'royal nut of Jupiter'.

Could be confused with

Black walnut (Juglans nigra). Common walnut has fewer leaflets than black walnut and its leaflets are more oval in shape and have smooth, untoothed edges.

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Where to find walnut

Walnut is native from south-east Europe to south-west China.

It’s been widely planted throughout the UK and has naturalised in lowland Britain (helped along by hoarding squirrels), in secondary woodland and hedgerows; and on river banks, field-borders and roadsides. It prefers well-drained, fertile and alkaline loam and is found in large gardens and parks.

Value to wildlife

The leaves are the foodplant for caterpillars of a number of micro moths, and the nuts are eaten by mammals, including mice and squirrels.

Mythology and symbolism

The walnut's botanical name, Juglans, originates in Roman mythology. According to an ancient myth, Jupiter, who was also known as Jove, dined on walnuts when he lived on earth. Therefore Romans called walnuts Jovis glans, meaning 'the glans of Jupiter’.

Walnuts with one cracked open on a wooden surface

Credit: Arco Images Gmbh / Alamy Stock Photo

Uses of walnut

Walnut was originally grown in the UK for its nuts. Later it was grown for its timber, which is fine with a decorative, wavy grain.

Walnut has a wide variety of medicinal qualities. The leaf is used in the treatment of conditions, including swelling of the skin, acne, ulcers, diarrhoea and excess sweating. The nuts are said to help lower cholesterol, while the shell is used in the treatment of blood poisoning. The leaf is also used in tanning agents and hair dyes.

Threats and conservation

The English walnut is susceptible to fungal diseases, as well as walnut blight which causes small black spots on the leaflets and can lead to dieback of new shoots and damaged fruit.

Walnut-leaf blotch can cause leaves to fall prematurely but doesn't cause lasting damage to the tree.