SPECIES CHARACTER
Description
Siberian elm is a fast-growing, small to medium-sized tree with an open, round crown of
slender, spreading branches. It generally measures 50-70 feet (15-21 meters) tall with a
spread equal to three-fourths its height. Its rough bark is gray or brown and shallowly
furrowed at maturity. Both the small, blunt buds and slender, smooth twigs are nearly
hairless. This elm is distinguished by its small, elliptic, smooth, singly-toothed leaves,
that reach lengths of approximately 0.8-2.6 inches (2-7 cm). Blades of the alternate,
simple leaves are short-pointed at the tip and tapering or rounded at the asymmetrical
base. The short-petioled leaves are dark green and smooth above, paler and nearly hairless
beneath, and yellow in autumn. Foliage is slightly pubescent when young, and firm at
maturity. Flowers are greenish, lack petals, and occur in small drooping clusters of 2-5.
The winged fruit of this hardy tree is a 1-seeded, smooth, circular or rather obovate
samara that is 0.4-0.6 inch (10-15 mm) wide and hangs in clusters.
Similar Species
Siberian elm is distinguished from American elm (Ulmus americana) and slippery elm
(Ulmus rubra) based on the following characteristics. Siberian elm has relatively small leaves
(rarely more than 2 inches or 5 cm long) that are symmetrical or nearly so at the base and
are once-serrate. Both American and slippery elm have leaves typically over 2.8 inches
(7 cm) long that are strongly asymmetrical at the base and are usually twice-serrate.
Siberian elm should be accurately identified before attempting any control measures.
If identification of the species is in doubt, the plant's identity should be confirmed by a
knowledgeable individual and/or by consulting appropriate books.
Distribution
Siberian elm is native to northern China, eastern Siberia, Manchuria, and Korea, and was
introduced to the U.S. in the 1860's. It is the hardiest of all elms and does well even in
areas with cold winters and long periods of summer droughts. Often planted in recent
decades because of its fast growth, it is now established at least from Minnesota south to
Arkansas and west to Utah.
Habitat
Because this elm tolerates a variety of conditions, such as poor soils and low moisture, it
is found in dry regions, along roadsides, in pastures, in grasslands, as well as in moist
soils along streams. It invades dry and mesic prairies, including sand prairies.
Life History
The tree flowers in spring before leaves begin to unfold. The samaras follow quickly and
are disseminated by wind, allowing the species to form thickets of hundreds of seedlings in
bare ground. Seeds germinate readily and seedlings grow rapidly.
Effects Upon Natural Areas
If there is a nearby seed source, the tree can invade and, in a few years, dominate prairie
areas, particularly if they have been subjected to past disturbance.
CONTROL RECOMMENDATIONS
RECOMMENDED PRACTICES IN NATURAL COMMUNITIES OF HIGH QUALITY
Initial effort in areas of heavy infestation
Girdling trees is the preferred management technique where practical. Girdle large trees
in late spring to mid-summer when sap is flowing and the bark easily peels away from the
sapwood. Girdled trees die slowly over the course of one to two years and do not resprout.
When girdling a tree, the bark and phloem must be removed from a band around the tree trunk
and the xylem must remain intact. If girdled too deeply, the tree will respond as if it
had been cut down and will resprout from the roots. Girdling can be done with an ax, saw,
or chainsaw. Two parallel cuts 3-4 inches apart, cutting through the bark slightly deeper
than the cambium are needed. The bark is knocked off using a blunt object like the head of
an ax. The girdles should be checked every several weeks at first to make sure they are
good and bark does not develop over the cut area.
If girdling is not an option, trees can be cut, and any resprouts that occur subsequently
should also be cut. If time constraints prevent cutting the new sprouts, the stumps
created by the initial tree cutting can be treated with Roundup (a formulation of
glyphosate) to prevent resprouting. While the Roundup label recommends a 50-100%
concentration of Roundup for stump treatment, a 10-20% concentration has proven effective.
Roundup can be applied to the cut stump either by spraying the stump with a low pressure
hand-held sprayer or wiping the herbicide on the stump with a sponge applicator to prevent
resprouting. Herbicides should be avoided except when there is not enough time to go back
and cut the sparse resprouts. Care should be taken to prevent contacting nontarget plants
with the herbicide. By law, herbicides only may be applied as per label instructions and
by licensed herbicide applicators or operators when working on public properties.
Seedlings can be pulled out by hand and small trees can be removed carefully by grub hoe.
Elm seeds blowing in from nearby areas are often a greater threat than resprouting of
established elms. Managers should eliminate nearby Siberian elms whenever possible.
Initial effort in areas of light infestation
Same as given above for heavily infested areas.
Maintenance control
A regular fire regime should control Siberian elm in fire-adapted communities. Siberian
elms should be controlled in areas surrounding a preserve whenever possible.
RECOMMENDED PRACTICES ON BUFFER AND SEVERELY DISTURBED SITES
Initial effort in areas of heavy infestation
Same as above except that labor-saving chemical methods may be preferred.
Initial effort in areas of light infestation
Same as above except that labor-saving chemical methods may be preferred.
Maintenance control
A regular fire regime should control this species in fire-adapted communities. Annual
mowing may be appropriate in some situations, especially where nearby seed sources cannot
be removed.
FAILED OR INEFFECTIVE PRACTICES
No biological controls are known that are feasible in natural areas.
ACKNOWLEDGEMENTS
Dr. Robert M. Mohlenbrock and the Southern Illinois University Press generously permitted use of illustrations from their Illustrated Flora of Illinois.
REFERENCES
Brown, L. 1986. Audobon society nature guides: grasslands. Alfred A. Knopf, Inc., New York. 853 pp.
Fernald, M. L. 1950. Gray's manual of botany, eighth edition. American Book Co., New York. 1632 pp.
Mohlenbrock, R. H. 1986. Guide to the vascular flora of Illinois. Southern Illinois University Press, Carbondale. 507 pp.
Rydberg, P. A. 1932. Flora of the prairies and plains of central North America. New York Botanical Garden, New York. 672 pp.
Swink, F. and G. Wilhelm. 1979. Plants of the Chicago region. Morton Arboretum, Lisle, Illinois. 922 pp.
PERSONAL COMMUNICATION
Apfelbaum, Steve. 1988. Applied Ecological Services, Juda, Wisconsin.
Harty, Fran. 1988. Division of Natural Heritage, Illinois Department of Conservation, Springfield, Illinois.
Martin, Mark. 1988. Wisconsin Department of Natural Resources, Madison, Wisconsin.
Nyboer, Randy. 1988. Division of Natural Heritage, Illinois Department of Conservation, Springfield, Illinois.
Packard, Steve. 1989. The Nature Conservancy, Chicago, Illinois.
Pearson, John. 1988. Iowa Natural Heritage Survey, Des Moines, Iowa.
Written for the Illinois Nature Preserves Commission by:
Jill Kennay and George Fell
Natural Land Institute
320 South Third Street
Rockford, Illinois 61108