The Japanese zelkova (Zelkova serrata) is a small to medium sized tree with branches extending straight upward in a sharp angle from a rather short trunk. The leaves are deciduous, oblong-ovate with sharp-toothed (serrated) edges. Bark is pale gray with horizontal lenticels, becoming mottled orange on older trunks. It is a common city tree but suffers from snow-induced branch breakage. Male and female flowers, small and green, appear on young shoots; they produce fleshy kidney bean-shaped fruit. This tree is native to Japan, Taiwan and eastern China. The tree was introduced to the West by von Siebold in 1830. Resembling its relatives, the elms, it is resistant to Dutch elm disease and been promoted in recent years as a substitute for the American elm (Ulmus americana). In Japan, the wood is used for furniture, lacquer ware and trays. It grows in low lying river valleys where the soil is rich and deep. In Japan it grows as a forest tree. Many old Japanese temples especially in the Kyoto region are built of its strong and durable timber. This is a Dutch Elm disease resistant elm relative.
Common name: Japanese Zelkova, Keyaki, Common Zelkova, Oriental-Elm
Scientific Name (family and order): Zelkova serrata (Thunberg) Makino (Ulmaceae, Rosales)
Species Origin: China, Japan, Korea
New Jersey Status: USDA Unreported
Habit: Small to medium sized tree. 40 – 70’ tall; bole 1 – 2 ½’ diameter; broadly spreading but often vase shaped. Branching starts low on the trunk where the short trunk divides all at once into many straight ascending branches.
Habitat: Zones 5 -8.
Trunk/Stem: Bark pale gray and smooth; horizontal lenticels; flaking with age revealing orange inner bark. The smooth bark is similar to beech.
Leaves: Deciduous, Simple, Alternate. Ovate to oblong-ovate, 4 ¼” long and 2” wide. rounded at base, slender, tapered tip (acuminate) and toothed, 6 – 13 teeth on each side. Adaxial surface dark green, rough; abaxial paler and nearly smooth; leaf turns yellow-orange-red in autumn. Leaves have pinnate venation with 9 – 15 veins per side.
Flowers: Monoecious. Both male and female flowers small and green on same plant without petals; Female flower borne singly in the leaf axils; male flower born in clusters at the base of the shoots. Yellow green in small clusters; very short stalks; bloom in spring.
Fruits and seeds: 1/8 – ¼” long ovoid brownish drupe. Borne singly at leaf base. Matures in autumn.