Juglans regia is a large, deciduous tree attaining heights of 25–35 m, and a trunk up to 2 m diameter, commonly with a short trunk and broad crown, though taller and narrower in dense forest competition. It is a light-demanding species, requiring full sun to grow well.
It is hardy to zone (UK) 5 and is not frost tender. It is in flower in June, and the seeds ripen in October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind.The plant is self-fertile.
The whole fruit, including the husk, falls in autumn. The seed is large, with a relatively thin shell, and edible, with a rich flavour.