Eastern cottonwood
Peuplier deltoïde
Populus deltoides Bartr. ex Marsh.Salicaceae (willow family)Origin: Eastern North America (native in Ontario)
Origin: Eastern North America (native in Ontario)
Eastern cottonwood is a large tree with a broad crown and sometimes multi-stemmed trunks.
Read more about Tree, Bark, Twigs
Leaves are triangular, with a pointed tip, a straight to heart-shaped base and large rounded teeth on the edges.
Read more about Leaves
Male and female flowers are tiny, clustered in long catkins on separate trees. Female catkins are green, male catkins are red.
Read more about Flowers
Fruits are capsules on long pendulous catkins appearing somewhat like green beads on a necklace.
Read more about Fruit
Eastern cottonwood is a large tree, up to 30 m (100') in height and 120 cm (47") in diameter. Open grown trees have a broad crown.
Some cottonwoods have multi-stemmed trunks.
The bark of young trees is smooth and yellowish-grey, and begins to fracture with age.
Mature bark is a darker grey and is deeply furrowed.
Twigs are stout, yellowish-brown with pores (lenticels), Terminal buds are up to 2 cm (3/4") long; lateral buds are shorter and angle out from the twig.
Buds are plump and pointed; greenish, covered with a sticky yellow resin.
Leaves are 5 - 10 cm (2" - 4") long, triangular, with a pointed tip, a straight to heart-shaped base and large rounded teeth on the edges.
The leaf stalk is nearly as long as the leaf. It is flattened at right angles to the leaf blade and there are 3 to 6 warty glands where they join.
Leaves, twigs and branches have an alternate arrangement on the branch.
In fall, the leaves turn yellow.
Male and female flowers are tiny, clustered in long catkins on separate trees, appearing before the leaves.
Male catkins are dark red extending to 5 - 7 cm (2" - 2 3/4") long at maturity.
The male catkins turn purple after releasing their pollen, often staining the sidewalk blue when they fall.
Female flowers are green with no petals.
Fruits are green egg-shaped capsules borne in long pendulous catkins15 - 25 cm (6" - 10"). They resemble green beads on a necklace.
In early summer, capsules split into 3 or 4 parts, to release hundreds of tiny seeds, each with silky white hairs for wind dispersal.
As the capsules open, female trees appear to be covered in cotton balls, actually tufts of seeds waiting for the wind.
Once the seeds are blown off the tree the "fluff" may pile up on the ground, cover other plants or coat the surface of nearby water.
Distribution
Eastern cottonwood is native to North America. One or other of its three subspecies grow in almost all Canadian provinces and the lower 48 states, preferring sandy habitats near rivers and lakes.
Derivation of names
Eastern cottonwood's common name is inspired by its silky white haired seeds, which when clustered together resemble masses of cotton. The species name deltoides means triangular, from the Greek letter delta and the word oides, meaning resembling, in reference to the shape of the leaves. The genus name Populus is the classical Latin name for poplars. As reported by J.L. Farrar in Trees in Canada, "the name Populus may have originated in ancient times when the poplar was called arbor populi (the tree of the people), because it was used to decorate public places in Rome."
Official status
Eastern cottonwood is the state tree of Kansas, Nebraska, and Wyoming.
Commercial use
Eastern cottonwood is a fast-growing tree and in warmer areas of the American South, it can grow several feet in a year. The wood is soft and weak, and is best suited for making plywood, pulpwood and chipboard. The leaves of eastern cottonwood and some of its hybrids are high in protein and have been used as feedstock for cattle and chickens.
Hybrids
Eastern cottonwood has been hybridizing either naturally or through cultivation with other poplars for centuries. This can complicate efforts to identify individual trees.
Wildlife value and human use
Eastern cottonwood is the favorite tree of the beaver, both as a food source and a building material. Tree cut down by beavers will resprout many new shoots from the stump, creating a coppice. Squirrels have been known to eat the emerging male catkins like corn-on-the-cob.
Eastern cottonwood's place in Toronto's urban forest
Eastern cottonwood grows naturally along the shores of Lake Ontario and along rivers. Eastern cottonwood was one of the first plants to colonize the newly constructed Leslie Street spit, its seeds having blown across the lake from populations nearby. In recent years, colonies of cormorants nesting in 
these trees have killed them by altering the soil chemistry with their guano.
Landscape value and potential for home planting
Eastern cottonwood is best suited to natural park settings or ravines. Due to its sticky buds, fluffy seeds and huge size (older trees can be expensive to prune or remove), eastern cottonwood is not suitable for home planting.
Pests and diseases: Eastern cottonwood is susceptible to various insects and diseases. For information see Natural Resources Canada fact sheet).
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