American sycamore (Platanus occidentalis) — identification, habitat & look-alikes

American sycamore is a large native tree found along streams and on floodplains across much of the eastern and central U.S. Pale patches on its upper bark and round seed balls, usually one per stalk, make it easy to recognize in winter. It is often called simply sycamore.

Appearance

Appearance: A large, fast-growing tree. Upper bark peels off in pale patches, while bark low on an old trunk can be dark and deeply furrowed.
Leaves: Big maple-like leaves 4–9 in (10–23 cm) wide with 3 to 5 shallow lobes. They open woolly and pale, and turn yellow-brown in fall.
Flowering time: Tiny flowers in round clusters appear with the new leaves, from late March in the southern part of its range to May in the north.
Fruit: Round brown seed balls about 0.8–2 in (2–5 cm) across ripen from September to November. They often remain through winter before breaking up in spring.

Look-alikes

London planetreePlatanus × hispanica

London planetree (Platanus × hispanica) usually has two seed balls on one stalk and leaves cut more deeply between the lobes. American sycamore usually has one seed ball, but a single leaf or a tree without fruit may be hard to place.

Why they get mixed upThe hybrid resembles its American sycamore parent and is also planted as a street tree.

Where it lives

Typical habitats: Stream banks
River bottomlands
Floodplains
Parks
Range: Occurs across much of the eastern and central US, from southwestern Maine to southern Wisconsin and Iowa, south to Texas and Florida. It also reaches southern Ontario and northeastern Mexico; some edge populations came from plantings.
Preferred conditions: Grows best in moist river-bottom soils and on floodplains. It tolerates seasonal flooding.
Flowering: Flowers Mar–May
Flowers Mar–May · Fruit Sep–Nov

Life cycle

Seed dispersal: Seeds travel by wind and water; spring floods often leave them on muddy flats, where they sprout readily.

Growing it

Care: Often grown as a shade tree in 4–9. Its large size, roots, and falling twigs and fruit need room.
Propagation: Young trees sprout back readily from the stump after being cut or damaged.

Name and classification

About the name: Also called American planetree or buttonwood.

Conservation

IUCN Red List: LCLeast ConcernLow risk of extinction
Threats: Sycamore can cause early leaf drop, especially in cool, wet springs.

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