How to Manage and ID American Sycamore

Sycamore is a massive tree reaching 75 to 90 feet in height, has a rapid growth rate, and tolerates wet and compacted soil. The white bark peels off in patches and is the most ornamental and identifiable trait. Pyramidal in youth, it develops a spreading rounded or irregular crown with age, supported by a few very large diameter branches.

Scientific name: Platanus occidentalis
Pronunciation: PLAT-uh-nus ock-sih-den-TAY-liss
Common name(s): Sycamore, American Planetree
Family: Platanaceae
USDA hardiness zones:: 4B through 9A
Origin: native to North America
Uses: large parking lot islands ; wide tree lawns ; recommended for buffer strips around parking lots or for median strip plantings in the highway; screen; shade tree; sidewalk cutout; residential street tree.

The National Arboretum in 1984 released two selections of Platanus occidentalis x Platanus orientalis which could prove to be superior to the parents: Platanus x acerifolia 'Columbia' - upright, orange-grey bark, five-lobed leaves; Platanus x acerifolia 'Liberty' - upright pyramid, five-lobed leaves, reportedly more resistant to powdery mildew and anthracnose, though not immune. Propagation is by seed, cultivars by hard or soft wood cuttings.

Height: 75 to 90 feet
Spread: 50 to 70 feet
Crown uniformity: symmetrical canopy with a regular (or smooth) outline, and individuals have more or less identical crown forms
Crown shape: round; spreading; pyramidal
Crown density: dense
Growth rate: fast
Texture: coarse

Trunk/bark/branches: droop as the tree grows, and will require pruning for vehicular or pedestrian clearance beneath the canopy; showy trunk; should be grown with a single leader;
Pruning requirement: needs little pruning to develop a strong structure
Breakage: resistant
Current year twig color: brown
Current year twig thickness: medium
Wood specific gravity: 0.49

Leaf arrangement: alternate
Leaf type: simple
Leaf margin: lobed; incised
Leaf shape: ovate; star-shaped
Leaf venation: pinnate; palmate
Leaf type and persistence: deciduous
Leaf blade length: 8 to 12 inches; 4 to 8 inches
Leaf color: green
Fall color: yellow
Fall characteristic: not showy

Sycamore branches should be 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 occasionally-occurring, upright, aggressive branches with tight crotches. It is also helpful to thin out the many branches which develop early on the central trunk.

Light requirement: tree grows in full sun
Soil tolerances: clay; loam; sand; acidic; alkaline; extended flooding; well-drained
Drought tolerance: high
Aerosol salt tolerance: moderate

Sycamore are best suited for soils which are moist and do not dry out. Dry soil can lead to short life for 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 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. Best not planted in yards due to messy habit, it should be saved for the toughest sites and supplied with some irrigation in drought. Allow at least 12 feet (preferrably more) of soil between the sidewalk and curb when planting as a street tree.
Sycamore is subject to attacks of anthracnose in wet, cool springs. The disease causes moderate to severe leaf drop and many trees are removed with this disease each year in our major cities. Many trees also defoliate early in the fall due to lace bug infestation. Therefore, do not overplant with Sycamore since they are so prone to problems.