Buttonwood Platanus occidentalis

Platanus occidentalis, or American Sycamore, is a large deciduous tree that may grow 75 to 90 feet tall and a trunk diameter of 10 feet or more. It is one of the largest hardwood trees, by diameter, in North America. When siting this tree on your landscape, keep in mind that this will be a large tree for a large space. It is native to North Carolina and can be found throughout the state, although it is more common and larger along streams and bottom land.

The tree has alternate leaves with 3 to 5 lobes and a coarsely toothed margin. The bark of the tree has a mottled look created by the darker outer layers peeling to expose the lighter inner layers. The bark peels off in patches and the whitened inner bark is the most ornamental trait of this plant. This plant is pyramidal in youth, and as it develops it becomes more rounded with an irregular crown and supported by a few large diameter branches. Branches are usually spaced two to four feet apart along the trunk to develop a strong structure. The dominant central leader which typically develops on sycamore usually assures that the structure of major limbs is desirable with little corrective pruning required other than removing the occassional upright, aggressive branches with tight crotches. In spring, very small flowers mature in clusters, typically one cluster to a stalk. The tree produces a spherical multiple of seeds borne on a 3- to 6-inch stalk. Each seed is tiny, winged, and 1/2 inch long.

Leaves commonly appear diagonally folded along two lines, such that the lateral sides project downwards, turning upward in fall as leaves dry to drop, hence in different planes. Plants in America were backcrossed against the London plant tree (P. x acerifolia). London plane trees have 3-5 gumballs per peduncle and deep sinuses while the backcrossed hybrids have 2 gumballs per peduncle, often with the lateral one aborting. Sinuses are difficult to discern as to depth.

This plant prefers full sun to deep, moist, fertile soils. It is tolerant of clay, sand, loam, alkaline, and wet soils. This plant has moderate drought tolerance. It is pollution tolerant, has a rapid growth rate, but has numerous pest and disease problems.

Insects, Diseases, or Other Plant Problems:  

Sycamore anthracnose is a significant disease that can severely damage the foliage and twigs, often precipitating premature leaf drop. Canker, leaf spot and powdery mildew may also occur. Insect visitors include borers, scale, Japanese beetles, caterpillars, and mites. When grown as a lawn tree, litter from twigs, large leaves, bark and fruiting balls can pose significant clean-up problems.

VIDEO Created by Elizabeth Meyer for "Trees, Shrubs and Conifers" a plant identification course offered in partnership with Longwood Gardens.