Botanical Name: Abelicea hirta – (Thunb.)
Species: Z. serrata
Synonyms: Abelicea hirta – (Thunb.)Schneid.,Corchorus hirtus – non L.,Zelkova acuminata – (Lindl.)Planch.,Zelkova formosana – Hayata.,Zelkova hirta – (Thunb.)Schneid.,Zelkova keaki – (Siebold.)Maxim.
Other Name : Zelkova serrata
Habitat: Native to Japan, Korea, eastern China, and Taiwan. Lowlands and mountains of C. and S. Japan. Valleys, beside streams at elevations of 500 – 2000 metres in China
A decidious Tree growing to 25m by 10m at a fast rate. It is often grown as an ornamental tree, and used in bonsai.
It is hardy to zone 5 and is frost tender. It is in flower from April to May, and the seeds ripen from September to November. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant).
Zelkova serrata is a medium sized deciduous tree usually growing to 30 meters (100 ft) tall. This tree is characterized by a short trunk dividing into many upright and erect spreading stems forming a broad, round topped head. The tree grows rapidly when young though the growth rate slows to medium upon middle age and maturity.
In summer, this tree has alternately arranged deciduous leaves. The leaves themselves are simple and ovate to oblong-ovate with serrated or crenate margins, to which the tree owes its species name “Serrata”. The leaves are acuminate or apiculate, rounded or subcordate at the base and contain about 8-14 pairs of veins. The leaves are rough on top and glabrous or nearly glabrous on the underside. They are green to dark green in spring and throughout the summer, though they change color in the autumn to a various assortment of yellows, oranges and reds. Leaves are 3-5 cm (1-2 in) long and 2-5 cm (0.8-2 inches) wide, on shoots that are approximately 12-13 cm (5 in) long. Petioles are 2-5 mm long.
Zelkova Serrata develops monoecious flowers in spring with the leaves. Buds are ovoid, acutish, with many imbricate, dark brown scales. They diverge at a 45 degree angle from the stem. The staminate flowers are shortly pedicellate and approximately 3mm in diameter, clustered in the axils of the lowers leaves. The pistillate flowers are solitary or few in axils of the upper leaves, sessile and usually about 1.5 mm in diameter. The flowers are yellow-green, not showy, and occur in tight groups along new stems. They give rise to small, ovate, wingless drupes that ripen in late summer to autumn. The drupe is green though matures to a brown color, subsessile and 2.5 to 3.5 mm in diameter.
To identify Zelkova Serrata, one would look for a short main trunk, low branching and a vase shaped habit. Its twigs are slender with small, dark conical buds in a zigzag pattern. The branches are usually glabrous. The bark is grayish white to grayish brown and either smooth with lenticels or exfoliating in patches to reveal orange inner bark. Branchlets are brownish purple to brown.
The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires moist soil.
This tree requires full to partial sun and prefers moist, well drained soils. A fertilizer rich in potassium and nitrogen encourages new vegetation and floral buds. It is adaptable and tolerant of heat, little water, nutrient poor soils and various pH. It should be periodically thinned to allow light into the inner canopy. Zelkova serrata is propagated by seeds, rooted stem cuttings and grafting. The seeds germinate without pretreatment, though the percentage is better when stratified at 41 degrees F for 60 days. Because germination requires stratification, the seed is best sown early in the year. To ensure survival it may be necessary to pot the tree and grow it in a greenhouse for its first winter. It may be reintroduced into its permanent habitat after the final frost.
The threats to this tree include colder temperature, which often result in twig dieback. It is highly resistant to Dutch Elm Disease, which makes it a good replacement tree for American Elm. Zelkova Serrata is similar in appearance to the elms, though may be distinguished by its unwinged fruit and leaves which are symmetrical rather than uneven at their base. Zelkova serrata also shows good resistance to elm leaf beetle and Japanese beetle.
Zelkova Serrata does have properties useful to man, though mostly superficial. It is planted as a lawn or park tree for its attractive bark, leaf color and vase shape. It provides good shade and has an easy fall cleanup. It is easy to transport, and often available in burlap form. Zelkova serrata is also commonly used for bonsai; its attractive shape and colors make it a popular choice for the art.
There are two varieties, Zelkova serrata var. serrata in Japan and mainland eastern Asia, and Zelkova serrata var. tarokoensis (Hayata) Li on Taiwan; the latter differs from the type in its smaller leaves with less deeply cut serration on the margins
An easily grown plant, it succeeds in almost any good soil, acid or alkaline, preferring a deep well-drained moist loam. Prefers a moderately sheltered position. Relatively shade tolerant. A fast growing tree. Dormant plants are very cold-tolerant, but they are sometimes damaged by late spring frosts when they are young. Plants are susceptible to Dutch Elm Disease, but the beetle that is the vector of this disease rarely feeds on Zelkova so infestation is rare. Plants in this genus are notably resistant to honey fungus.
Seed – best sown in a cold frame as soon as it is ripe. Stored seed requires stratification and should be sown as early in the year as possible. Germination rates are variable. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Edible Parts: Leaves. Young leaves – cooked
Medicinal Uses : Not known.
Wood – tough, hard, beautifully grained. Used for tool handles, construction, furniture etc
It is often grown as an ornamental tree, both in its native area and in Europe and North America. The first cultivation outside of Asia was by Philipp Franz von Siebold, who introduced it to the Netherlands in 1830.
Numerous cultivars have been selected, including ‘Fuiri Keaki’ (variegated leaves), ‘Goblin’ (dwarf), ‘Goshiki’ (variegated leaves), ‘Green Vase’ (tall, narrow crown), ‘Green Veil’ (pendulous branchlets), ‘Iruma Sango’ (fastigiate), ‘Nire Keaki’ (semi-dwarf), ‘Pulverulenta’ (variegated leaves), ‘Spring Grove’ (upright crown), ‘Variegata’ (variegated leaves), ‘Village Green’ (grows more rapidly than ordinary seedlings and develops a straight smooth trunk. Hardier than trees of Japanese origin photos), ‘Variegata’ (weak growing, small leaved form with a narrow white rim around the margin of the leaf),’Parkview’ (selection with good vase-shape, size similar to species) and ‘Urban Ruby’ (red autumn colour). It has also hybridised with Zelkova carpinifolia in Europe, the hybrid being named Zelkova × verschaffeltii.
Keyaki wood is valued in Japan and used often for furniture, such as tansu.
The tree is a symbol of japanese many cities, Saitama Prefecture , Miyagi Prefecture,Fukushima Prefecture,Fukushima-shi,Abiko-shi,Tachikawa-shi,Yokohama-shi,Machida City in Tokyo Metropolis District and more