Walnuts (Juglans) are a genus of about 21 deciduous trees, grown mainly for their edible nuts and valuable timber, with J. regia (English walnut) the main nut species. They need full sun, shelter from wind, and room to grow.
Family
Juglandaceae (Walnut family)
Grows as
Tree
Light
Full sun
Water
Water deeply during dry spells while young; mature trees are fairly drought tolerant.
Soil
Deep, well-drained loam; tolerates a range of soils but dislikes waterlogging.
Temperature
Hardy in temperate climates, roughly to -25 °C once established; late spring frost can damage new growth.
How easy
Moderate
Safety
Not known to be toxic
Edible
Yes, some parts
About
Walnut trees are any species of tree in the plant genus Juglans, the type genus of the family Juglandaceae, the seeds of which are referred to as walnuts. All species are deciduous trees, 10–40 metres (33–131 ft) tall, with pinnate leaves 200–900 millimetres (7.9–35.4 in), with 5–25 leaflets; the shoots have chambered pith, a character shared with the wingnuts (Pterocarya), but not the hickories (Carya) in the same family.
The 21 species in the genus range across the north temperate Old World from southeast Europe east to Japan, and more widely in the New World from southeast Canada west to California and south to Argentina.
How to grow it
The two most commercially important species are J. regia for timber and nuts, and J. nigra for timber. Both species have similar cultivation requirements and are widely grown in temperate zones.
Walnuts are light-demanding species that benefit from protection from wind. Walnuts are also very hardy against drought.
Uses
The raw edible seed of walnut is composed of 4% water, 14% carbohydrates, 15% protein, and 65% fat. In a 100 gram amount, walnuts provide 654 calories and are a rich source (≥20% of Daily Value) of protein, dietary fiber, the B vitamins, niacin, vitamin B6, and folate, and several dietary minerals, particularly manganese.
Text excerpted from the Wikipedia article Juglans by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.