Ulmus pumila Seeds | Siberian Elm
LATIN NAME: Ulmus pumila
COMMON NAME: Siberian Elm
Plant Profile
Ulmus pumila is the elm of the dry north, and it is a different plant from the broad-crowned elms of Europe. It is small, seldom past fifteen metres, with a short trunk that forks low and a crown of slender, slightly drooping branches. The leaves are small, narrow and simply toothed, and they come out early in spring, before most other trees have moved.
The species runs from eastern Siberia through Mongolia and northern China to Korea, on dry slopes, in river gravel and along field edges. It is planted in enormous numbers in the shelterbelts of northern China, where its tolerance of wind, drought, salt and poor soil matters more than its timber. In North America it was introduced for the same reasons and has become a weed of alleys, railway lines and prairie towns.
Science & Biotechnology
Siberian elm is resistant to Dutch elm disease, and that resistance is why it was moved around the world. The fungus Ophiostoma novo-ulmi grows poorly in its xylem, and the tree plugs infected vessels quickly. The same resistance made it a rootstock for European elms, though grafts often fail after a decade because the two species grow at different rates.
The tree is also a heavy seed producer, and the samaras ripen in May and germinate within days of landing. Seed that falls on bare ground comes up in a week, and a seedling can reach a metre in its first season. That combination, disease resistance and fast establishment, is what makes it invasive on disturbed ground, where it forms dense stands and shades out native grasses.
Uses & Benefits
In northern China the tree is a shelterbelt species, planted in rows to slow wind and hold soil along field margins and railways. The leaves and young twigs are cut as fodder for sheep and goats, and the bark was used for rope and for coarse cloth in times of scarcity.
The timber is hard and tough but the trees are small and often forked, so it goes to tool handles, posts and firewood rather than to furniture. In Chinese medicine the bark is used as an astringent and the seed as a diuretic, and the samaras are eaten in some districts, though they are thin and not worth gathering where anything else is available.
Growing from Seed
Seed loses viability within weeks, so sow it as soon as it is ripe in late spring. Press it into moist soil, cover lightly, and keep it warm; germination is in five to ten days. Cuttings of softwood taken in June root easily, and root suckers can be lifted in winter where a named tree is wanted.
The tree grows on almost anything, including gravel, clay and salted road verges, and it needs no care once established. That is the problem as much as the virtue: it self-sows into hedges, cracks in pavement and prairie remnants, and cutting it back only forces regrowth from the roots. Plant it where its spread can be controlled, or choose a native species instead.
Our Take
A tough tree for the worst ground, and a serious weed anywhere it can seed freely. Useful in a shelterbelt, unwelcome in a garden.
Related Reading
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