Japanese Walnut
Juglans ailantifolia · Deciduous, Broadleaf, Hardwood
Plant Family
Juglandaceae
Tree Category
Nut Tree, Shade Tree, Ornamental
Variety / Cultivar
Likely the Heartnut variety (Juglans ailantifolia var. cordiformis) based on the ornamental garden setting and spreading canopy.
Hardiness Zones
USDA Zones 4-8. Adaptable to temperate climates with cool winters.
About This Tree
A medium-sized deciduous tree reaching a spreading, rounded form. It features a broad, open canopy with massive, spreading branches. It is known for its tropical appearance due to very large pinnate leaves.
Leaf Characteristics
Large, alternate, pinnately compound leaves (up to 2-3 feet long); consisting of 11-17 leaflets. Leaflets are ovate-oblong with serrated margins, medium green, and hairy on the underside.
Bark Characteristics
Light gray to grayish-brown bark. Smoother on younger trees, becoming shallowly furrowed or fissured with age, developing a distinctive interlacing pattern.
Growing Information
Origin Region
Native to Japan and Sakhalin (Russia). Cultivated in North America and Europe.
Growing Season
Leafs out in late spring (avoiding late frosts); flowers from May to June; fruits ripen in autumn; enters dormancy in late autumn with yellow fall color.
Sunlight & Water Needs
Full sun for best nut production; prefers moist, well-drained, fertile soil. Moderate drought tolerance once established but prefers consistent moisture.
Mature Size
Height: 40-60 feet; Spread: 40-60 feet. Moderate growth rate. Lifespan of 60-150 years.
Special Characteristics
Produces edible nuts (especially Heartnuts); noted for its resistance to walnut bunch disease compared to Butternut trees. High timber value and striking ornamental architecture.
Wildlife & Ecology
Attracts squirrels and other rodents who feed on the nuts. Host plant for various moth larvae. Provides excellent nesting sites for birds in its broad canopy.