Horticulture Highlight: Katsura Tree
Smell is a potent wizard that transports us across
thousands of miles and all the years we have lived.
Many visitors to Mount Auburn come not only to be in the here and now, but also to be conveyed to another place, perhaps across time, that includes significant, even spiritual memories. For some, plant fragrances may influence or even embellish one’s feelings or mood. Throughout the calendar year, flowers with signature aromas, such as tree peony, crabapple, lilac, rose, linden and many others may evoke deep responses. With some plants it is their fragrant foliage such as sweet fern, monarda and Russian sage. Each autumn I anticipate being fondly transported to yesteryear from a less expected source, the senescing and fallen leaves of the Katsura tree, Cercidiphyllum japonicum. This scent, for me, recalls cotton candy from myriad locations of childhood, decades in the past.
…our shadows growing longer as we walked
russet, yellow, and every now and then
a brilliant red
the scent of the fallen Katsura leaves
hangs in the air …
Katsura tree, Cercidiphyllum japonicum is a choice shade tree reaching 40-60-feet in height, which often grows with multiple stems, having broad graceful arching side branches. Authoritative plantsman, Michael Dirr writes in his much-referenced Manual of Woody Landscape Plants, “…overwhelming in overall attractiveness; if I could use only one tree this would be my first tree…” Currently native to China and Japan, fossils representing an ancestral extinct species have also been found at sites in North America and Europe. Today the genus Cercidiphyllum, considered relatively primitive, contains but two species within its own monotypic family, CERCIDIPHYLLACEAE.
Handsome, like shadows
slow-moving on a Japanese screen…
Early spring, before its leaves appear, tiny inconspicuous apetalous flowers provide an easily overlooked reddish hue to the leafless branches. These dioecious flowers occur on separate male or female trees, as we have also seen with ginkgo and holly. When successfully fertilized, the female flowers will produce ½-inch-long follicles (dry dehiscent fruits) in the summer. At immaturity these green fruits might remind one of tiny bananas. When ripened by October, these pod-like follicles will change color to brown and split open releasing tiny winged seeds. The emptied follicles persist on trees assisting with winter identification of female katsuras.
The cordate shaped leaves, 2 to 4” long and wide have a crenate (rounded-tooth) margin. In early spring emerging leaves display a transitory beautiful reddish color, eventually turning a slight bluish-green. Autumn color, often preceding its arboreal landscape companions, tends towards yellow to apricot/orange. The near-end of life of colorful foliage and even dead leaves is what creates the smell which Keller postulates transports me (and perhaps others) across many of the years I have lived. Katsura leaves contain high levels of maltol, present throughout the life of the leaves, but which peaks during senescence. A very diffuse maltol perfume barely detectable from a single leaf, accumulates from the tree’s canopy and recently dropped leaves creating a delightful scent. As with many fragrances scent is in the description of the beholder, cotton candy, caramel, apricots, brown sugar and cinnamon rolls are some of the detections I have heard attributed to the source of sweet fragrance that Katsura leaves emit.
O wild West Wind, thou breath of Autumn’s being,
Thou, from whose unseen presence the leaves dead
Are driven, like ghosts from an enchanter fleeing…
On a future visit to Mount Auburn, look for some of our more notable Katsura Trees on Lime Avenue, Rosebay Avenue, Meadow Road, Pond Road, Daphne Path, Azalea Path, Wren Path, Vernonia Path and Ilex Path among other locations.
…And the dead leaves lie huddled and still,
No longer blown hither and thither…