Exclamation! London Plane Tree (Platanus x acerifolia Exclamation!™) is probably one the most improved cultivars to date (USDA hardiness zones 4-8). Exclamation! was introduced by Dr. George Ware at the Morton Arboretum and released through the Chicagoland Grows® program.

Exclamation! develops a strong central leader, a uniform upright pyramidal shape (when young), a vigorous growth rate, and is highly resistant to both anthracnose and powdery mildew diseases. Mature height is thought to be approximately 60 feet tall and 45 feet broad. Under optimum conditions young trees may grow 3 feet annually and 1 1/2 feet after 8-10 years. The tree seems to take on a stovepipe form around its base as reaches maturity.

London planetrees resist the harsh environs associated with parking lot islands, median traffic strips, and urban street plantings. They stand up to urban air pollution, poor drainage, compacted soil, wet or droughty soils. Its medium green foliage color holds all summer long, turns yellow for a short interval in autumn before abscising. Numbers of gumball fruits are reportedly less than on other planetrees. Its exfoliating patchwork bark of white, tan, brown and green is absolutely exquisite and develops very early in the tree’s life.

In urban areas plant London Plane 35-40 feet apart. They become a massively large tree in a short time. Include a root barrier along the edge of the sidewalk and curb. Roots grow aggressively and can lift sidewalks and curbs, invade sewer pipes, and crack building foundations. London planetree may be pruned into hedges, screens, and arbors. Mature trees do holdup to extensive root pruning.