The Siberian elm is usually a small to medium-sized, often bushy, deciduous tree growing to 25 m tall, the d.b.h.
to 1 m; the bark is dark gray, irregularly longitudinally fissured.
The branchlets are yellowish gray, glabrous or pubescent, unwinged and without a corky layer, with scattered lenticels.
The winter buds dark brown to red-brown, globose to ovoid.
The petiole is 4-10 mm, pubescent, the leaf blade elliptic-ovate to elliptic-lanceolate, 2-8 × 1.2-3.5 cm,  the colour changing from dark green to yellow in autumn.
The perfect, apetalous wind-pollinated flowers bloom for one week in early spring, before the leaves emerge, in tight fascicles (bundles) on last year's branchlets.
However, flowers emerging in early February are often damaged by frost, consequently the species was dropped from the Dutch elm breeding programme.
Each flower is about 3 mm across and has a green calyx with 4–5 lobes, 4–8 stamens with brownish-red anthers, and a green pistil with a two-lobed style.
Unlike most elms, the Siberian elm is able to self-pollinate successfully.

The wind-dispersed samarae are whitish tan, orbicular to rarely broadly obovate or elliptical, 1-2 × 1-1.5 cm, glabrous except for pubescence on stigmatic surface; the stalk 1-2 mm, the perianth persistent.
The seed is at centre of the samara or occasionally slightly toward apex but not reaching the apical notch.
Flowering and fruiting occur March to May. Ploidy: 2n = 28.
The tree also suckers readily from its roots.

The tree is short-lived in temperate climates, rarely reaching more than 60 years of age, but in its native environment may live to between 100 and 150 years.
A giant specimen, 45 km southeast of Khanbogt in the south Gobi, with a girth of 5.55 m in 2009, may exceed 250 years (based on average annual ring widths of other U. pumila in the area).
The Siberian elm is usually a small to medium-sized, often bushy, deciduous tree growing to 25 m tall, the d.b.h. to 1 m; the bark is dark gray, irregularly longitudinally fissured. The branchlets are yellowish gray, glabrous or pubescent, unwinged and without a corky layer, with scattered lenticels. The winter buds dark brown to red-brown, globose to ovoid. The petiole is 4-10 mm, pubescent, the leaf blade elliptic-ovate to elliptic-lanceolate, 2-8 × 1.2-3.5 cm,  the colour changing from dark green to yellow in autumn. The perfect, apetalous wind-pollinated flowers bloom for one week in early spring, before the leaves emerge, in tight fascicles (bundles) on last year's branchlets. However, flowers emerging in early February are often damaged by frost, consequently the species was dropped from the Dutch elm breeding programme. Each flower is about 3 mm across and has a green calyx with 4–5 lobes, 4–8 stamens with brownish-red anthers, and a green pistil with a two-lobed style. Unlike most elms, the Siberian elm is able to self-pollinate successfully.
The wind-dispersed samarae are whitish tan, orbicular to rarely broadly obovate or elliptical, 1-2 × 1-1.5 cm, glabrous except for pubescence on stigmatic surface; the stalk 1-2 mm, the perianth persistent. The seed is at centre of the samara or occasionally slightly toward apex but not reaching the apical notch. Flowering and fruiting occur March to May. Ploidy: 2n = 28. The tree also suckers readily from its roots.
The tree is short-lived in temperate climates, rarely reaching more than 60 years of age, but in its native environment may live to between 100 and 150 years. A giant specimen, 45 km southeast of Khanbogt in the south Gobi, with a girth of 5.55 m in 2009, may exceed 250 years (based on average annual ring widths of other U. pumila in the area).
Ulmus pumila