Culture
Easily grown in average, medium wet, well-drained soils in full sun. Established trees tolerate some drought. Prefers rich, moist loams. Generally tolerant of urban conditions.
Noteworthy Characteristics
Zelkova serrata, commonly called Japanese zelkova, is a medium to large deciduous tree, typically growing to 50-80’ tall with a spreading, generally upward-branching, vase-shaped crown. It is native to Japan, Taiwan and eastern China. It is noted for its graceful shape, clean foliage, attractive bark and resistance to Dutch elm disease. Zelkova has in fact been promoted in recent years as a substitute for American elm (Ulmus americana) because of its resistance to Dutch elm disease. Insignificant small green flowers appear in spring as the foliage emerges. Flowers give way to small, non-showy, ovate, wingless drupes that ripen in autumn. Oblong-elliptic medium green leaves (to 3” long) with coarse, ciliate marginal teeth and acuminate tips. Fall color is variable, ranging from undistinguished yellow to attractive shades of yellow-orange to red-brown. Smooth gray bark in youth exfoliates with age to reveal orange-brown inner bark. Zelkova is valued as a commercial timber tree in Japan.
Genus name may refer to the original Republic of Georgia name (Zelkova carpinifolia is native to the Caucasus).
Specific epithet and additional common name of sawleaf zelkova both refer to the serrated leaf margins.
‘Green Vase’ is an open pollinated seedling that was introduced into commerce in the 1980s by Princeton Nurseries in Princeton, New Jersey. U.S. Plant Patent PP05,080 was issued August 2, 1983. Patent documents claim this cultivar is distinguished from species plants and other cultivars by its narrower upright growth with vase-shaped crown, more rapid growth when young, better winter hardiness, better drought resistance in heavy soils, larger/paler green foliage, orange-bronze (rather than rusty red) fall color and good foliar resistance to air borne pollutants. ‘Green Vase’ grows taller than ‘Village Green’.
Problems
No serious insect or disease problems. Highly resistant to Dutch elm disease. Phloem necrosis, wilts and cankers may occur. Insect visitors include leaf miner, beetles and scale. Spider mites can be a problem in hot, dry summers.
Uses
May be used as a lawn, shade or street tree.