Tree Board Spotlights Kentucky Coffeetree Grove
The board selected the grove for its 2022 Treasure Tree designation.
The Hillsborough Tree Board has selected a small grove of Kentucky coffeetree saplings on the Riverwalk greenway for its 2022 Treasure Tree designation. The grove is located on the north side of the Eno River near the Weaver Street Market entrance to Riverwalk.
“Kentucky coffeetree is one of the rarest native tree species,” said Justin Bennett of the North Carolina Forest Service, who confirmed the identification of the trees with on-site examination.
The identification of this grove was initially a mystery for Tree Board members. After some initial misidentification, the puzzle was solved by Katy Porter, a volunteer helping to remove invasive species along Riverwalk. She found documentation of the trees on the Vascular Plants of North Carolina search engine, which is maintained by the North Carolina State Parks. The documentation noted that only two non-cultivated populations of these Kentucky coffeetrees have been identified in the state. One was identified on the banks of the Eno River in Hillsborough in 1951. The other was identified in Chapel Hill’s Battle Creek Park in 2006.
About the tree
The Kentucky coffeetree, Gymnocladus dioicus, is a unique tree with large, leathery 6- to 12-inch pods and very large leaves made up of smaller leaflets. Its common name refers to its use by early settlers, who roasted the seeds encased in the pods and brewed them as a substitute for coffee, which was expensive and hard to find outside of coastal cities. Some Native American tribes found medical uses for parts of the tree, and the hard seeds were widely used as dice in a game found in many pre-colonial cultures.
Unless roasted, the seed is poisonous for both humans and animals. For this reason, the tree is considered an ecological anachronism, like the Osage orange and honey locust trees, which also have fruit that is inedible to modern wildlife. It is thought that extinct large American herbivores, like the wooly mammoth, once ate and dispersed the seed. Coffeetree seeds no longer spread from the mother tree except along streams where they may be transported downstream. Although the fruit is toxic to animals and birds, the tree still has wildlife value as a larval host for both the bicolored and bisected honey locust moths.
Because the leaves of this tree are late to emerge and early to fall, the Kentucky coffeetree is without leaves, or naked, five or six months of the year. Its Greek genus name, Gynnocladus, means “naked branch.” The tree’s bipinnately compound leaves can reach up to 3 feet long and 2 feet wide, with numerous 2-inch leaflets, making them one of the largest leaves of our native trees. The coffeetree can reach a height of 60 to 75 feet with a 40- to 50-foot spread at maturity.
Although widely distributed, the Kentucky coffeetree is a rare forest tree and is mostly found in small groves or as a single specimen, primarily in fertile bottomlands in the Midwest. With its bold form, contorted branching, unique bark and decorative clusters of large pods, Kentucky coffeetree has a distinctive profile. It is a beautiful and easy-to-grow large shade tree, tolerant of many soil types, flooding, drought and storms. Tree expert Michael Dirr writes, “To know her is to love her. A wonderful native species that tolerates the worst stress nature and humanity can impose.”
The Tree Board’s Treasure Tree program is intended to create awareness of and give recognition to the preservation of significant trees in the Hillsborough area. See the Tree Board page for information on nominating a tree, for a list of designated trees or for a brochure on a self-guided walk of treasure trees.