Japanese Walnut

Japanese walnut is a broad, deciduous tree with a rounded crown and long pinnate leaves. Spring catkins and clusters of developing nuts add seasonal interest, while the generous canopy makes this a tree for a spacious site. ## Form and landscape role Allow substantial room for this tree to mature: [Oregon State University](https://landscapeplants.oregonstate.edu/plants/juglans-ailantifolia) describes a broad, round crown and a mature height of 40–65 feet, while [Van den Berk Nurseries](https://www.vdberk.co.uk/trees/juglans-ailantifolia/) reports a 15–20 metre height and width. The large compound leaves typically have 11–17 leaflets. Male catkins hang from the branches and the female flowers develop into clusters of hard nuts in sticky, hairy husks. ## Growing conditions Plant in full sun and fertile soil. Van den Berk notes that the species grows in almost any soil if it is fertile; leave open ground around the trunk and crown, since this tree does not tolerate paving. Oregon State lists it as hardy to USDA Zone 5 and native to Japan. The [RHS profile](https://www.rhs.org.uk/plants/511446/juglans-ailantifolia/details) also records Japan as its native range and describes Juglans as deciduous trees with catkins and usually edible nuts. ## Maintenance Choose a location where the mature canopy and seasonal nut drop will not obstruct paths or patios. The nuts are valued as food in Japan, though Oregon State notes that recovering intact kernels from the thick shells can be difficult. Clear fallen husks and nuts where they create a slipping or cleanup problem.