Identifying the Common American Sycamore

Its bark looks like a jigsaw puzzle

Common American Sycamore

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The American sycamore (Platanus occidentalis) is a massive tree that can attain the largest trunk diameter of any eastern U.S. hardwood. The native sycamore has a broad, outreaching canopy and its bark is unique among trees—you can recognize a sycamore just by looking at the jigsaw shapes of its bark.

A sycamore can also be identified by its broad, maple-like leaves and button-shaped seeds. The complexion of its trunk and limbs, however, is a unique jigsaw of green, tan, and cream shapes, a coloring that reminds some people of military or hunting camouflage. It belongs to one of the planet's oldest clans of trees (Platanaceae), dated by paleobotanists as over 100 million years old. Sycamore trees are among the longest-lived trees in the world, reaching ages of 500 to 600 years.

The American sycamore, or western planetree, is North America's largest native broadleaf tree and is often planted in yards and parks. Its hybridized cousin, the London planetree, adapts well to urban living. The "improved" sycamore is New York City's tallest street tree and is the most common tree growing in Brooklyn, New York.

Description and Identification

American sycamore leaf

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Common Names: American planetree, buttonwood, American sycamore, buttonball, buttonball-tree.

Habitat: America's largest broadleaf tree is a fast-growing, long-lived tree of lowlands and old fields in the eastern deciduous forest.

Description: The sycamore (Platanus occidentalis), a tall, grand-canopied tree with broad, maple-like leaves and multicolored, patchy bark, is often one of the largest in its forests.

Uses: Sycamores are valued for timber and widely planted as shade trees.

Natural Range

A map of distribution of the sycamore tree

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Sycamores grow in all the American states east of the Great Plains except for Minnesota. The native range extends from southwestern Maine west to New York and into extreme southern Ontario, central Michigan, and southern Wisconsin. It grows in southern Iowa and eastern Nebraska, eastern Kansas, Oklahoma, and south-central Texas and extends as far south as northwestern Florida and southeastern Georgia. Some stands are found in the mountains of northeastern Mexico.

Silviculture and Management

Sycamore tree bark

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Sycamores are best suited for moist soils that don't dry out; dry soils can shorten the life of this moisture-tolerant tree. Sycamores have been cursed by horticulturists and others for being messy, dropping leaves and twigs throughout the year, particularly in dry weather. However, the tree grows in places unsuitable for most plant growth, such as small cutout planting pits along urban sidewalks and other areas with low soil oxygen and high pH.

Unfortunately, aggressive roots often raise and destroy sidewalks. The dense shade created by the tree’s canopy might interfere with the growth of lawns. In addition, leaves that fall to the ground in autumn reportedly release a substance that can kill newly planted grass. Because of its messy habits, sycamores are best not planted in yards; save them for the toughest sites and supply irrigation during droughts. Allow at least 12 feet (preferably more) of soil between the sidewalk and curb when planting as a street tree.

Insects and Diseases

Lesions on a sycamore leaf

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Pests: Aphids will suck the sap from sycamores. Heavy aphid infestations can deposit honeydew on lower leaves and objects beneath trees, such as cars and sidewalks. These infestations usually do no real harm to the tree.

Sycamore lace bugs feed on the undersides of the leaves, causing stippling. The insects leave black flecks on the lower leaf surface and cause premature defoliation in late summer and early fall.

Diseases: Some fungi cause leaf spots but usually aren't serious. Anthracnose fungi, however, cause early symptoms on young leaves resembling frost injury. When the leaves are almost fully grown, light brown areas appear along the veins. Later the infected leaves fall off, and trees might be nearly completely defoliated. The disease can also cause twig and branch cankers. After the initial attack, the trees can send out a second crop of leaves, but repeated attacks can lower tree vigor. Use a properly labeled fungicide that has been recently recommended by tree authorities to combat anthracnose.

Fertilization helps trees withstand repeated defoliation. Powdery mildew causes a white fuzz on the tops of leaves and distorts leaf shape. A bacterial leaf scorch can kill trees over several growing seasons, causing significant tree loss. Leaves affected by the bacteria appear scorched, become crisp, and curl up as they turn a reddish-brown. Stress cankers form on limbs of trees stressed with drought. There are a few cost-effective remedies, and land management to support the trees' health is the recommended strategy.