American Sycamore, while not the tallest tree, is considered the most massive tree, as defined by its circumference, in the entire eastern half of the United States, where is it native including all of Ohio.
This species is easily identified by its height, its spreading canopy with several massive branches, and its white bark in winter. The paths of creeks and rivers can be easily seen from a distance in winter by following the white bark of barren Sycamore canopies.
While many Ohio landscapes contain its European cousin, London Planetree, which is more resistant to anthracnose, this tree towers above most others in native environments.
Also known as Sycamore or American Planetree, this tree easily reaches heights of 80 feet tall and 60 feet wide, but can grow much larger. As a member of the Plane Tree Family, it is closely related to other Planetrees, and distantly related to Sweetgum.
Planting Requirements - American Sycamore prefers deep, moist, rich soils of variable pH that are either well-drained or moderately drained, as it is often found naturally along the edges of bodies of water, and in wet areas of fields or woodlands. It tolerates much drier and poorer soils, but does not like the city pollution that London Planetree survives. It is found in zones 4 to 9, in full sun to partial sun.
Potential Problems - American Sycamore is very prone to annual infections of anthracnose, a fungus that destroys the new growth in spring. This causes dieback of the emergent leaves and stem, and subsequently the lateral buds break (either at the base of the new growth, or from previous year's branchlets) and form a whorled pattern of new stems, which resemble witches' broom growth. This secondary growth occurs in late spring and usually becomes the growth of the season, as drier weather does not encourage new fungal growth.
Other diseases and pests may occur on American Sycamore, but the most serious problem after anthracnose is usually hollow trunks, which eventually make the tree subject to storm damage, and of course getting too big for its space in urban areas. In both cases, the tree may need to be removed.