42. LONDON PLANETREE
Platanus x acerifolia
The London Planetree is a cross (hybrid) between the American Sycamore tree and the Asian Planetree (Platanus orientalis) dating back to the mid- 1600s. Speculation is it hybridized naturally in Spain, but this is anecdotal. In cities choked with the smoke/smog of the Industrial Revolution there was a need for a hardy, pollution tolerant urban tree. The London Plane was that answer.
4 SEASON, BARK
The bark of the London Planetree is similar to the American Sycamore, but there are two subtle differences. The upper part of the tree shows the same inner-bark as the Sycamore, but the color is greenish, not white (left). The second difference is that the exfoliation of the bark on London Planes extends all the way down to the base of the tree (right). Sycamore has more traditional bark on its lower trunk.
Spring flowers are nearly identical to American Sycamore. Green flowers are female, red are males. One subtle difference. The female flowers (and seed balls) may hang singly or in clusters of two, three (here) or more on a single stalk. The Sycamore only has a single seed ball on one stalk.
Sycamores and London Planes are stately trees. While the Sycamores in The Grove are tall and narrow, here we see the London Planetree with plenty of room to expand. Measuring DBH (Diameter-at-Breast-Height, 4.5 ft.) for this tree yields 21 inches in 2023. This info strongly supports it was planted by the Hunter Family, circa 1950s.
The seed balls of the London Planetree start in Spring, mature in Summer, and drop from the tree starting in late fall. The clusters may be hard to see in Summer (left). The seed balls also persist on the tree over the winter, and the now dark seed balls may still be seen the following Spring (right).
SEED BALL, CLOSE-UP
This is 1/2 of a London Planetree seed ball (left). On the right, an extreme close-up of the individual seed/nut and the hair-like fibers (achenes) attached to them. The achenes aid wind dispersion and help the seed to float in water - an excellent way for seeds to travel.
FALL COLOR (1)
Fall color of both Sycamores and London Planes can be hard to predict, and it often changes within the same season. This was October 20, 2022.
FALL COLOR (2)
This is 10 days later, November 1, 2022. The yellow has changed to a stunning rust color and contrasts beautifully against against a cobalt sky, the ebbing grasses of the wildflower meadow, and the historic trees in the center of the Arboretum.