Kentucky Coffee Tree

The Kentucky coffee tree (Gymnocladus dioicus) is an interesting native tree in the legume family that has a wide distribution across the eastern and Midwestern part of this country but it is found in relatively small numbers. Other than the US the only other parts of the world this genus is found is China and Burma.

The Kentucky coffee tree gets its name from the fact that settlers used the seeds to make a coffee like beverage. It should be noted however that the beans and seed pod are poisonous and special care needs to be taken in the roasting of the seeds.

The Latin name Gymnocladus means naked branch, is descriptive of a tree that is slow to develop its leaves in the spring and one of the earliest trees to shed their leaves in the fall. In most regions this tree has leafless branches for a 6 month period.

The Kentucky coffee tree is a medium sized tree that usually grows about 80’ feet tall and has a 3’ diameter at maturity. The leaves of the Kentucky coffee tree are very distinctive being binately compound meaning that there are two rows of leaflets for each petiole.

The Kentucky coffee tree also has distinctive bark that is brownish grey in color and scaly much like the bark of the black cherry tree. There are no fine branches on this tree so the branches are stout and stubby much like the black walnut tree.

The seed pods of this tree are also very distinctive being large and leathery. It is difficult to open these seed pods unless they are scarified or they rot away in damp conditions.

Kentucky coffee tree prefers growing on limestone soils and can tolerate damp to droughty conditions. The trees can reproduce from sprouts and they often occur in small clumps in the forest. The most common location of this tree are wide floodplains and alluvial terraces where it is growing in conjunction with sycamore, catalpa, river birch, pin oak, and silver maple.

The wood is light brown in color and very rot resistant. The wood is used frequently by cabinet makers.

Kentucky coffee tree is thought to be a more ancient species that was probably more common thousands of years ago when larger herbivores roamed our region. These animals probably opened the seed pods so that the seed would germinate and grow. Now in the absence of animals to open the seed pods the Kentucky coffee tree must depend on moisture to rot away the seed so the tree is more common in wetter areas.

Despite its idiosyncrasies the male Kentucky coffee tree is widely planted as a street tree and in the landscape. The tree can grow in a multitude of site conditions, is very tolerant of drought, and is not susceptible to many insects or disease. Males are most often used because they do not possess the large seed pods.

Article by Mike Kay, FCFCDB

Nature note for 1/29/22