Identify Common American Sycamore (Platanus Occidentalis)

Common American Sycamore
The American sycamore tree (Platanus occidentalis) is readily identified by its patchy bark and large maple-like leaves.). Panoramic Images/Getty Images

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

Sycamore can also be readily 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 which reminds some people of military or hunters' camouflage. It is a member of one of the planet's oldest clan of trees (Platanaceae) and paleobotanists have dated that family to be over 100 million years old. Living sycamore trees are among the longest-lived trees in the world, reaching the ages of five to six hundred 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 very well to urban living. The "improved" sycamore is New York City's tallest street tree and it is the most common tree growing in Brooklyn, New York.

Description and Identification

Autumn leaf on a white background

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

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

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

Uses: Sycamore is valuable for timber and is also widely planted as a shade tree.

The Natural Range of Sycamore

A map of distribution of sycamore tree in north america

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Sycamore grows in all of the U.S. states east of the Great Plains except for Minnesota. Its 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; it extends as far south as northwestern Florida and southeastern Georgia. Some stands are also found in the mountains of northeastern Mexico.

The Silviculture and Management of Sycamore

sycamore tree bark
Sycamore bark.

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Sycamore is best suited for soils which are moist and do not dry out: dry soils can shorten the life of this wet-site-tolerant tree. Sycamore has been cursed by horticulturists and others because it is said to be messy, dropping leaves and small twigs throughout the year, particularly in dry weather. However, the tree grows in places which appear most unsuitable to plant growth, such as in small cut out planting pits in urban sidewalks and in other areas with low soil oxygen and high pH.

Unfortunately, aggressive roots often raise and destroy nearby sidewalks. The dense shade created by the tree’s canopy may interfere with the growth of lawn grasses beneath it. In addition, the leaves which fall to the ground in autumn reportedly release a substance which can kill newly planted grass. Because of its messy habits, sycamore is best not planted in yards but rather saved for the toughest sites and supplied with some irrigation in drought periods. Allow at least 12 feet (preferably more) of soil between the sidewalk and curb when planting as a street tree.

Insects and Diseases of Sycamore

lesions on sycamore leaf
Sycamore Tar Spot (Rhytisma acerinum) lesions on Sycamore (Acer pseudoplatanus) leaf.

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Pests: Aphids will suck the sap from sycamore. Heavy aphid infestations can deposit honeydew on lower leaves and objects beneath the tree, 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 a stippled appearance. 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 are usually not serious.
Anthracnose, however, causes 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 may 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 which 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 the tree over a period of several growing seasons and can thus cause significant tree losses. 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 few cost-effective remedies, and land management to support the health of the tree is the recommended strategy.

Pest information courtesy of USFS Fact Sheets.