Dumbarton Oaks Katsura Tree Conservation
Washington, DC | 2023-2024
Collaboration Ron Henderson, Kurato Fujimoto, Hans Friedl, Ben Jensen Dumbarton Oaks Gardens and Grounds Jonathan Kavalier, Marc Vedder, Ricardo Aguilar, Austin Ankers, Rigoberto Castellon, Kim Frietze, MJ Garcia, James Lavahun, Luis Marmol Dumbarton Oaks Rare Books Anatole Tchikine
Trees (1) The team also installed hoozue to conserve the beech tree on theBeech Terrace and a group of cherry trees on Cherry Hill at Dumbarton Oaks.
Katsura Orihon, the project sketchbook by Ron Henderson, is now in the collection of Dumbarton Oaks Rare Books.
The katsura tree (Cercidiphyllum japonicum) at Dumbarton Oaks is among the oldest of the species in North America. Records indicate that this specimen was mature at the time that the landscape architect, Beatrix Farrand, began her work with Mildred Bliss to design and construct the gardens of Dumbarton Oaks which are considered one of the greatest American gardens of the twentieth century.
Farrand noted the “magnificent Katsura tree, and an equally fine Japanese Maple” in her Plant Book For Dumbarton Oaks. She wrote, “These trees and shrubs make a foliage border to the lawn difficult to equal for character and delicacy. The old plants, such as the Cercidiphyllum and the Japanese Maples, were growing in these places when the land was acquired by Mr. and Mrs. Bliss. The new planting has been made in an effort to bring out these beautiful old plants…”
A survey of the property by James Berrall, dated July 5, 1922 shows a 20-inch tree in the present location of the katsura, flanked by a 12-inch Japanese Maple. These markings correspond with Farrand’s notes, and back-dating from a 20-inch katsura in 1922, it is believed the tree was 20-30 years old at the time of the survey. This would correlate with the availability of katsura trees from the Washington, D.C.-based nursery of John Saul, who first listed the tree in his inventory in 1895.
This legacy specimen in characterized by an octopus-like branching habit with long, horizontal branches that are at risk of structural damage. Evidence indicates that they have previously broken or pruned back to sprouts as several branches exhibit a distinct vertical growth just back from the location where the branches were cut. Revitalization of this legacy tree by promoting new growth -- while also supporting at-risk branches and limbs -- is the ambition of the work.
Japanese master gardener, Kurato FUJIMOTO (藤元 藏人) of Kanazawa, Japan was invited to assess and lead a conservation effort using branch supports, known as hoozue (ほおづえ), to rejuvenate this venerable tree. The term, hoozue (where hoo=chin, and zue=cane), refers to the bodily posture of resting one’s chin in the palm of one’s hand while resting one’s elbow on a table. Hoozue were fabricated and installed at key structural locations along branches and at the branch extremities where the addition of the hoozue promotes new leaf, branch, and biomass growth to collect energy to return to the tree’s core. This technique, to promote growth at the extremities, contrasts with current North American practices which recommends re-trenchmen -- pruning outer branches to concentrate energy in the tree’s core.
(excerpt from Henderson, R. and Kavalier J. Hoozue: Indigenous Japanese Technique for Preservation of the Legacy Katsura Tree at Dumbarton Oaks, Landscape Architecture Frontiers, Volume 12, Issue 3, June 2024.) https://doi.org/10.15302/J-LAF-1-050060
