(Populus deltoids occidentalis)
Adopted on February 1, 1947 -
The Plains Cottonwood, Populus
deltoids occidentalis, was adopted
as Wyoming state tree on February
Populus is the Latin
name for poplars. Deltoides refers to
the triangular-shaped leaves.
Occidentalis is Latin for "west."
American Indians may not have
distinguished the two since different
names have not been identified. The
Lakota know them as canyŠh'u, meaning
"peel off wood," and the Omaha as
Cottonwoods are members
of Salicaceae, the willow family, along
with willow (Salix spp.) and quaking
aspen (Populus tremuloides ). The leaves
are deciduous, alternate, simple, 3 to 6
inches (8 to 15 cm) long,
triangular-shaped with serrate margins.
Flowers occur in the spring before the
leaves appear, they are dioecious and in
hanging catkins . Fruits are 1/4 inch
(.64 cm) long, 3 or 4 valved capsules.
The twigs are yellowish brown and
smooth. The terminal buds are long and
resinous. The bark is ash-gray and
divided in thick flattened ridges with
Plains cottonwood is
native throughout the central plains
from Texas to Manitoba. Cottonwood, as
with willow, is a pioneer species. It is
also very intolerant of competition.
Cottonwoods tend to seed into a new
flood plain and develop as pure,
even-aged stands. As cottonwoods mature
(about 50-70 years after the stand
begins), they are gradually replaced by
the more tolerant ash and elm.
The two greatest threats to
cottonwood are fire and drought.
Cottonwoods are very vulnerable to fire,
light burns will kill seedlings and
saplings. Hotter fires can severely
injure the bark on older trees, which
opens the trees up to decay. While they
are moderately drought tolerant, a
long-term dry spell will lead to death.
- Life Span: Cottonwood is
not a very long-lived tree. As with
their close relative, willow,
cottonwoods usually live about 70
years. A 120 year old cottonwood is
a very old tree.
- Size: While cottonwoods
may not live very long, they are
very fast growing so big trees are a
common sight. The largest cottonwood
is in Grundy County, Illinois. It is
373 inches (947 cm) in
circumference, 132 feet (40 m) tall
with a branch spread of 99 feet (30
m). The largest in South Dakota is a
plains cottonwood near Richland in
Union County. It is 344 inches (873
cm) in circumference, 114 feet (35
m) tall with branch spread of 113
feet (34 m).
- Significance: Wood of the
cottonwood is light. It was
important as a construction material
for the American Indians and
European settlers. Cottonwood,
because of its abundance, was used
to build barns and houses.
Occasionally large cottonwoods, 4 to
6 feet (123 to 183 cm) in diameter,
were cut down and burned out to form
a crude canoe. Today cottonwood is
used for pulp and sometimes
lightweight furniture. Cottonwood is
also used as a windbreak species
although it is not highly
recommended due to its short life
The Dakota ate the sweet inner bark
of young sprouts of cottonwood trees in
the spring. They also fed young
cottonwood branches to their horses. A
dye was made from the leaf buds. The
Sacred Pole, used in ceremonies of the
Omaha Indians, is made of cottonwood.
||Plantae -- Plants
||Tracheobionta -- Vascular
Spermatophyta – Seed plants
||Magnoliophyta – Flowering
||Magnoliopsida – Dicotyledons
||Salicaceae – Willow family
||Populus L. – cottonwood
Populus deltoides Bartr.
ex Marsh. – eastern cottonwood
Populus deltoides Bartr.
ex Marsh. ssp. monilifera (Ait.)
Eckenwalder – plains cottonwood
Exerpts from: Publication of the
Eastern and Plains Cottonwood fact
sheet was funded by the S.D.
Department of Agriculture, Division
of Forestry, Pierre, SD.
Source: U.S. Department of