A small tree, 10 to 30 ft high, sometimes a shrub. Leaves oval or ovate-lanceolate, acute to acuminate at the apex, tapered or rounded at the base, and not unequal-sided there as elms usually are, rather coarsely toothed except at the base, 3⁄4 to 21⁄4 in. long, 1⁄3 to 1 in. wide, dark green and quite glabrous (or with minute tufts of down in the vein-axils) beneath; stalk downy, 1⁄12 to 1⁄6 in. long. Flowers borne on the naked shoots in spring, on very short stalks, and in clusters. Samaras circular or rather obovate, deeply notched at the top, 1⁄2 in. across, the seed about the middle.
Native of Central Asia (with a southern limit in south Tibet and the inner parts of the northwest Himalaya), E. Siberia, Mongolia, N. China and Korea. It is allied to U. carpinifolia, differing in the smaller leaves with fewer lateral veins and the smaller samaras. It is shrubby only in very cold or exposed habitats, and becomes a tall tree in northern China, whence derive most if not all of the examples now in collections. It was introduced by Purdom for Messrs Veitch from the Peking region, while the two trees at Colesbourne were, most remarkably, raised by H. J. Elwes from a branch 2 in. thick, received from Peking, which grew when potted up (Elwes and Henry, op. cit., p. 1927). These measure 59 × 6 ft and 65 × 63⁄4 ft (1971). There is an example at Wakehurst Place in Sussex of about the same size, which has so far (1979) been unaffected by the Dutch elm disease (another healthy tree was blown down in the winter of 1978/9). A smaller example at Kew is one of the few remaining elms in the collection.
In the United States U. pumila is much planted, especially in the Middle West, being both hardy and drought-resistant, besides being so far little affected by the Dutch elm disease. It has been crossed there with U. rubra, one clone of this parentage being ‘Coolshade’, introduced in 1946.
U. ‘Pinnato-ramosa’. – A very elegant, vigorous-growing, small-leaved elm, sent out by Dieck from the Zöschen Arboretum at the end of the last century as U. pinnato-ramosa. The branchlets, more downy than those of U. pumila, are arranged in two opposite rows (distichously) and the leaves are longer pointed, but otherwise similar to those of U. pumila. The Dieck plants were said to have come from western Siberia but similar plants have been found in Turkestan, or been raised from seed collected in that area. This elm has been identified with U. pumila var. arborescens Litvinov.