Ohio Trees

Bulletin 700-00

Populus – Poplar

Poplars are deciduous trees with rounded or angled branches. Leaves may be alternate, lobed, toothed, or entire. Buds are imbricate with many scales. Flowers are dioecious and borne in pendulous catkins. Fruit is a capsule containing seeds with basal hairs that allow the seeds to be carried by the wind.

Key to Populus Species

Description of Species

White (Silver) Poplar–Populus alba

White poplar was introduced from Europe and Asia but has become naturalized. Silver poplar is longer lived than some of the other poplars. It is a large tree, standing 75—100 feet in height with a massive, broad head. Like many other members of the genus, it is undesirable for ornamental purposes because the roots often clog older underground tile and drains. Plastic pipe is resistant to damage.

Bark is gray to light green or white with black, diamond-shaped scars on old trunks. The bark and foliage color give the tree its common name. Young twigs and buds are often white and woolly as well. Leaf petioles (stalks) are not flattened vertically and are rounded, or nearly so. Leaves are three- to five-lobed, and coarsely toothed, especially on vigorous shoots. Foliage color is dark green above with thick, white or silver hairs covering the lower surface.

Carolina Poplar

Carolina Poplar–Populus 3canadensis

The Carolina poplar has a widespreading habit and is not narrow or upright. This tree is widely scattered and does not occur in great abundance except when planted in cities and towns for shade. It is unsatisfactory for shade because it begins to shed its leaves by midsummer, and limbs are easily broken by wind. Aggressive growth of the roots often results in clogging of drainage tiles and drain pipes that do not have cemented joints.

The leaves are simple, alternate, and ovate or triangular in outline. Leaf bases are more rounded than square, while leaf margins are finely toothed. Leaves are a shiny, dark green above, paler beneath, and 2—4 inches (5—10 cm) in length and width. Leaves are supported by flattened, slender petioles that are 1 1/2—3 inches (4—8 cm) long. No gland is present at the base of the leaf blade.

The winter buds are conical, pointed, and 1/2—3/4 inch (1—2 cm) long. Buds are covered with chestnut brown, resinous scales. Side buds curve away from the twig. The third bud scale is nine-tenths as long as the bud. Buds are small and viscid (sticky). The twigs are smooth and yellow to yellowish-green in color. Twigs are moderately stout and slightly angled.

The pendant male flowers are borne in dense catkins and appear before the leaves. Female flowers are also in catkins but have fewer flowers per cluster. Seeds mature before the leaves. Carolina poplar is a cross between the black poplar and the cottonwood and is best described as a series of cultivars. ‘Eugenei' is a male clone and thus would not produce fruit.

Eastern Poplar (Cottonwood)–Populus deltoides

Cottonwood is a large tree, sometimes 100 feet high and 3—4 feet in diameter, with large, upright, spreading branches forming an open, broad crown. It is one of the most rapidly growing native Ohio trees, common in floodplains and swampy areas.

This tree is distributed over the entire state and attains great size when growing along rich bottom lands and in major drainage valleys. In northwestern Ohio, the poplar, or cottonwood, is a common associate of forest trees such as elm, green ash, sycamore, silver maple, red oak, and swamp white oak.

The leaves are simple, alternate, 2 3/4—4 3/4 inches (7—12 cm) long, and 2 1/2—5 inches (6—13 cm) wide. The leaf blade is broadly triangular in shape with a translucent margin. Leaves are pointed with coarsely toothed margins, which are somewhat rounded and curved. The mature leaf surface is smooth, except along the margins which tend to be somewhat hairy. Foliage color is shiny green above and somewhat paler and smooth below. Leaf bases are usually square, or nearly heart-shaped. Petioles are flattened and 1 1/2—3 inches (4—7 1/2 cm) long. Leaves have glands present at the base of the leaf blade.

Eastern Poplar (Cottonwood)

The twigs are stout, angular, smooth, and yellowish-brown in color. Buds are slender with a conical-shape. Terminal buds are resinous and 1/2—3/4 inch (1 1/4—2 cm) long. The terminal bud is often five-angled. Side buds do not curve away from the twig. The third bud scale is not over three-fourths as long as the bud. On young trees, the bark is light greenish-yellow and smooth, gradually becoming ash gray and deeply furrowed on mature trees.

The flowers appear before the leaves. Pollen-bearing flowers and seed-producing flowers occur on different trees. Female flowers produce large amounts of seed with basal hairs in June. The fruit is a three- to four-valved capsule arranged in drooping tassels. The seed looks something like a dandelion seed and is borne by the wind for great distances. Seeds may occur in sufficient numbers to turn the ground beneath the tree white.

The wood is soft, not durable, and warps easily but is suitable for various uses such as boxes, crates, shelves, lath, sheathing, and wooden ware. It is highly prized by paper manufacturers who use the pulpwood for the manufacture of the highest-grade, gloss magazine and book paper.

Southern Poplar–Populus deltoides missouriensis

Distribution of the southern poplar is confined more to the southern portion of the state along flood plains and stream valleys. Like the cottonwood, the southern poplar can be a massive tree. They can reach 100 feet in height and have a trunk 3—4 feet in diameter. The tree is upright with large, spreading branches forming an open, broad crown.

Southern poplar is a tree that is similar to the Eastern poplar except that the twigs are smaller and the branches are more angled. Leaves are 4—6 1/2 inches (10—16 1/2 cm) long, larger than those of the cottonwood, with glands present at the base of the leaf blade. The leaf margins have translucent borders and toothed margins. Leaves are not typically triangular in shape, but are broadly ovate or round.

Balm of Gilead Poplar–Populus 3gileadensis

Probably introduced from Asia, the Balm of Gilead poplar attains a height between 50—75 feet and has spreading branches. This tree may be a hybrid between P. deltoides and P. balsamifera. Bark is gray and smooth. Buds are covered with a varnish-like, sticky resin and are quite pleasant to smell. Twigs are reddish-brown in color and have terminal buds that are 1/2 inch (13 mm) long and usually much larger than side buds. The first scale of the side bud is borne on the side opposite the twig. Twigs are fragrant.

Leaves are not lobed, but are broad and have a cordate leaf base. Leaves are 4 3/4—6 1/2 inches (12—16 1/2 cm) in length, and about 3 inches (7 1/2 cm) wide. Foliage has a dark green color with whitish hairs beneath the leaf becoming dense along the veins. Less pubescence is present on the upper leaf surface. Petioles are not flattened but are rounded, or nearly so.

Monoecious flowers open in March or April. Since this is a sterile clone, seedlings are not a problem. Despite the fact that the tree is sterile, it has escaped cultivation in many areas of Ohio as it spreads by suckers. Like other members of the genus, it is undesirable for ornamental purposes because the roots often clog underground tile drains, although modern, plastic sewer pipes with cemented joints are not harmed. Wind damage is common as well.

Bigtooth Aspen (Poplar)–Populus grandidentata

This tree is nearly as common as the quaking aspen and grows in association with it. This aspen is a rapid grower that sometimes reaches a height of 80 feet and a diameter of 20 inches.

It is a tree that prefers moist, sandy, rich soils, especially along the borders of streams, ponds, and lakes. Its natural range extends from Nova Scotia, Canada, westward to Minnesota, southward to the Ohio River, and along the Appalachians to North Carolina. In Ohio, it is uniformly distributed throughout the state.

Bigtooth Aspen (Poplar)

The bark is smooth and greenish-gray in color. The mature bark of older trees is dark and divided into broad, flat ridges at the root crown. The buds are gray, downy, and somewhat larger than those of the other species of aspen. Twigs are gray and pubescent when young, becoming reddish- to orangish-brown at maturity.

The leaves distinguish this species from the quaking aspen. Leaf blades are up to 2 1/4—4 inches (5 3/4—10 cm) long, dark green above, and gray and woolly beneath when young. Foliage is nearly bloomy when mature. In contrast to the regular- and fine-toothed edges of the quaking aspen, the edges are coarsely and irregularly toothed. Like the quaking aspen, this tree lacks the translucent borders seen in other poplars.

The flowers are in catkins similar to those of the other poplar species. Pollen-bearing flowers and seed-producing flowers occur on different trees. The pollen-bearing flowers are arranged in drooping catkins, 1 1/2—2 1/2 inches (4—6 cm) long. The wood is light brown with thin, weak, soft, and nearly white sapwood. It is used in the manufacturer of paper, excelsior, and, to a small extent, woodenware.

Swamp Poplar (Cottonwood)

Swamp Poplar (Cottonwood)–Populus heterophylla

This is a tree of low, wet swamps and the flood plains of the larger streams and rivers. It is reported from Ashtabula County westward to the old black-swamp areas of northwestern Ohio and south to the Ohio River.

The seeds are carried far by winds and germinate on wet sandy soils. The tree attains a height of 70—90 feet and a diameter of 3 feet. Branchlets are stout and dull brown or gray in color. Buds are slightly sticky. The branches are usually short, forming a narrow, round-topped crown.

The leaves are broadly ovate, 3—6 inches (7 1/2—15 cm) wide and 4—7 1/4 inches (10—18 cm) long. The leaf blade gradually narrows at the tip and is slightly rounded toward the base. Margins are usually finely toothed. Foliage is dark green above and pale and smooth below. Foliage is tomentose when young, becoming glabrous or somewhat hairy as it ages. Petioles (leaf stems) are round and 2—3 inches (5—7 1/2 cm) long.

The flowers bloom in early spring and are in catkins. Female catkins have few flowers, while the male catkins are larger and many-flowered. The fruit contains the tiny seeds supported by "cotton" and is borne on female, or pistillate, trees. Male trees produce no fruit, and the flowers are shed after pollen is shed. The fruit ripens before leaves are full-grown. The male and female flowers occur on different trees.

The wood is light and soft. The wood requires special attention while drying in order to prevent warping. Swamp poplar makes good paper pulp. Like other members of the genus, the roots often clog older underground tile and drains. Moist areas may require a tree such as this that is adapted to low oxygen soils.

Lombardy Poplar–Populus nigra "Italica"

Lombardy poplar is an upright, ascending cultivar of the European black poplar that was introduced from Europe and western Asia. Branches are closely pressed to the main trunk, growing nearly upright, and forming a narrow crown or head. This cultivar grows rapidly and has been used principally in gardens for screens and tall backgrounds.

Lombardy Poplar

Leaves have a flattened petiole. The leaf blade is 2—3 inches (5—7 1/2 cm) long and triangular in shape with a translucent border. Leaves are medium green with a wedge-shaped base. This tree is very short-lived, rarely living more than 10—15 years. Lombardy poplar is attacked by a number of canker-causing fungi that cause decline and death in a few years. Fungicides are not effective.

Quaking Aspen–Populus tremuloides

The aspen is one of the most widely distributed trees in North America. In Ohio, aspen trees are found mostly in the northern regions of the state. The tree extends to the tundra line in the north and from the Atlantic to the Pacific oceans.

Aspen is a small- to medium-sized tree reaching heights of 80 feet and diameters of 20 inches but is usually somewhat smaller. The tree reproduces readily from root suckers and may form clonal colonies of great size and age. Seedlings are eaten readily by deer and other mammals, which can prevent seedling propagation. This is a serious problem in the western United States where deer and elk herds are numerous, preventing seedlings from surviving. This results in large areas covered by a single clone that may be more than a thousand years old. Old clones have old-age problems, and the size of the clonal patches reduces cross pollination, further reducing biodiversity.

		Quaking Aspen

The young branchlets are reddish-brown and shiny but turn gray and become roughened after the first year. The winter buds are about l/4 inch (6 mm) long, pointed, and slightly resinous. Buds have a brown, varnished appearance and are often curved toward the twig. The bark is thin, yellowish-brown to orangish-green in color, and often roughened.

The leaves alternate along the stem and are broadly oval in shape. Leaves are short, pointed at the end, and toothed along the margin with small swellings or "glands" on the teeth. Foliage is green and shiny above and dull green below. Foliage is 1 1/4—2 3/4 inches (3—7 cm) long, equally wide, and often slightly bloomy beneath. Unlike the cottonwood, the leaves do not have translucent borders. The flattened petiole results in the fluttering of the leaves and the name, quaking aspen.

The flowers, like those of all the poplar family, are of two kinds born on separate trees. Male catkins are about 2 inches (5 cm) long, while the female, or pistillate, catkins are up to 4 inches (10 cm) in length. The fruit ripens in late spring or early summer, before the full expansion of the leaves, and contains tiny, rounded seeds.

The wood is light brown, surrounded with nearly white sapwood. It is light, not strong, and extensively used as pulpwood for book and magazine paper and for boards for food containers.