Description
Zelkova –
There are about 5 or 6 deciduous monoecious or hermaphrodite trees, occasionally shrubby, within the Ulmacea family, in this genus. They occur naturally in scrub and woodland in Asia Minor across cool climate areas of Western Asia to China and Japan. They are grown for their attractive habit and alternate, pointed elliptical, heavily veined and serrated edged, dark green leaves. The bark is sometimes an attractive feature also. The leaves change to yellow then russet or red, in autumn. Zelkova species are closely related to, and often confused with elms (Ulmus), differing in their unwinged fruits and in their leaves, which are not even at the bases. The very small, inconspicuous, male or hermaphrodite green flowers are borne singly or in small clusters in spring, the males from the lower axils of the shoots, the hermaphrodites higher up, and the flowers are followed by insignificant, spherical green fruits. Zelkova species and cultivars are handsome specimen and street trees, most of them suitable for open parkland and larger gardens. Z. abelicea and dwarf cultivars of Z. serrata are better suited for use in smaller gardens. Good substitutes to elms (Ulmus), where Dutch elm disease is prevalent.
Grow in deep, fertile, moist, but well drained soil in sun or partial shade with plenty of water during summer. Shelter from strong winds.
Prone to bacterial canker, Elm-leaf beetle, and horse chestnut scale.
Z. serrata ‘Green Vase’ – Z. keaki – Japanese Zelkova – This deciduous often vase shaped tree is the most widely grown of the Zelkova’s, and grows to 40’ feet tall and 60’ feet wide. It has smooth gray bark, peeling to reveal light gray to yellowish patches. Thin, dark green, alternate narrowly oblong, pointed heavily veined leaves, 2-5” long, each with up to 16 teeth on either side and shiny undersides. In spring it bears, inconspicuous greenish flowers. The leaves turn orange-brown to bronze-red in autumn.
Zones 5-9
