Crooked Run Valley
slippery elm (Ulmus rubra)
Ulmus fulva Michx.
CONFIRMATION STATUS: Confirmed.
TAXONOMY: The currently accepted scientific name for slippery elm is
Ulmus rubra Muhl. There are no recognized subspecies, varieties, or forms.
Slippery elm is commonly crossed with Siberian elm (Ulmus pumilia).
Hybrids of rock elm (Ulmus thomasii) and slippery elm have been observ-
ed in the wild, although these hybrids do not seem to be common.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS: Slippery elm is a
native, medium-sized, deciduous tree reaching 60 to 70 feet (18-21 m)
on average sites and 135 feet (41 m) on the best sites. In the forest, it
has a straight bole with the trunk dividing into widespreading limbs high
up the tree. The crown is broad and rather flat topped. The perfect flowers
form dense packed clusters. The root system is shallow but widespreading.
REGENERATION PROCESSES: Seeds of slippery elm are larger than
those of many of the native elms. Dispersal is by gravity and wind.
Slippery elm sprouts readily from the stump or root crown. Seedlings pro-
duces sprouts from rhizomes. Slippery elm also reproduces by layering.
Rootstocks of slippery elm are grafted to hybrid elms.
SITE CHARACTERISTICS: Slippery elm grows best on moist, rich
soils of lower slopes, streambanks, river terraces, and bottomlands but
is also found on much drier sites, particularly those of limestone origin.
Examples of sites on which it is an important species are floodplains,
terraces, and well-drained uplands in east-central Illinois; the northern
Mississippi River floodplain; alluvial terraces in western Pennsylvania;
lower ravine slopes and uplands in central New York. Slippery elm can
persist on poorly drained soils that are occasionally flooded for periods
of 2 or 3 months, but it does not reproduce or grow well if flooding is
frequent or prolonged.
SUCCESSIONAL STATUS: Slippery elm is one of the more shade-toler-
ant species. It is much more tolerant than quaking aspen (Populus tremul-
oides) but slightly less tolerant than sugar maple (Acer saccharum). Repro-
duction is erratic under fully stocked stands. In a river terrace forest in
east-central Illinois, slippery elm was present in most size classes, but no
seedlings were present. A nearby upland coppice, however, contained num-
erous slippery elm seedlings. Slippery elm is frequently a component of the
SEASONAL DEVELOPMENT: The flowers open before the leaves,
from February to May, depending on weather and location. Seeds ripen
from April to June and are dispersed by wind and water as soon as they
GENERAL DISTRIBUTION: Slippery elm's range extends from south-
western Maine west to extreme southern Quebec, southern Ontario, New
York, northern Michigan, central Minnesota, eastern North Dakota; south
through eastern South Dakota, central Nebraska, southwestern Oklahoma,
and central Texas; then east to northwestern Florida and Georgia. Slippery
elm is uncommon in the part of its range south of Kentucky; it is most abun-
dant in the southern part of the Lake States and in the cornbelt of the Mid-
Slippery elm is susceptible to many of the same diseases as American elm.
It is attacked and killed by Dutch elm disease, caused by the fungus Cerato-
cystis ulmi. Throughout much of its range, it is also killed by elm yellows or
elm phloem necrosis. These two diseases are so virulent and widespread
that slippery elm seldom reaches commercial size and volume as a forest
tree, and it is being replaced as a street tree in many localities. In mixed-
hardwood stands, bark stripping by deer is more frequent on stems of
saplings and on roots of pole-sized trees.
SKY MEADOWS DISTRIBUTION:
Tree specimens can be found on trails marked in red.
Appalachian Trail/Old Trail
South Ridge/North Ridge
Rolling Meadows/ Lost Mountain
HABITAT TYPES AND PLANT COMMUNITIES: Slippery elm, like
American elm, prefers moise, rich soils, generally near a water source,
although it does grow in dryer conditions. It is often found with maples
(Acer spp.), oaks (Quercus spp.), pines (Pinus spp.), although is is usually
less adaptable to the drier conditions that oaks and pines can be found. It
was once a significant component of the Appalachian oak forests, northern
hardwood forests, northern hardwoods - fir forests, oak - hickory - pine
forests, but has been seriously diminished by Dutch elm's disease.
Common associates of slippery elm include hickory (Carya spp.), box elder
(Acer negundo), blackgum (Nyssa sylvatica), black walnut (Juglans nigra),
hackberry (Celtis occidentalis), and honeylocust (Gleditsia triacanthos).
IMPORTANCE AND USES: The seeds of slippery elm are eaten by birds
and small mammals. Deer and rabbits browse the twigs.
Slippery elm trees provide thermal cover and nesting sites for a variety of
primary and secondary cavity nesters.
Slippery elm is not an important lumber tree. The wood is considered infe-
rior to that of American elm (Ulmus americana) even though both are
mixed and sold together as soft elm. Slippery elm is used in the manufac-
ture of boxes, baskets, crates, and barrels.
The bark of slippery elm contains a mucilaginous substance that was used
as a treatment for coughs and diarrhea by the early settlers. It has also
been used as a street ornamental, but its use is limited due to Dutch elm