Tree of the Week: Kentucky Coffeetree

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  This past week I gave a talk at OSU’s Urban Landscape Pesticide Applicator Training school at the 4-H Center on Main Campus in Columbus and admired the adjacent Donald Mayhew Memorial Tree Grove at Chadwick Arboretum developed by Dan Struve and friends.  It is growing up before our eyes and the Kentucky coffeetrees (Gymnocladus dioicus) are demonstrating their majesty.


  Kentucky coffeetree is a native tree that is planted as a tough urban survivor in streetscapes, and is tolerant of limey soils and tree pits (Chicago urban foresters list it as one of their five toughest street trees). It has a starkly coarse yet beautiful appearance in the winter landscape, and its fairly early fall defoliation and late spring foliation make it perfect if long seasons of sun penetration are desired.


 The bipinnately compound leaves are huge, from 6-10 inches long, though the axillary buds that prove that the elaborately branching foliage is of such long multi-leafleted leaves are tiny and sometimes difficult to find amongst woolly hairs in the leaf axils. The seeds in the fruit pods (it is a legume in the Fabaceae) were used as a poor substitute for coffee by settlers.


fruits and foliage of Kentucky coffeetree


  These seeds are beautiful and were used for games and as jewelry by Native Americans” the seeds are a shiny bright lima bean-like green early, but deepen to a hard texture and turn coffee-brown color as they age. Kentucky coffeetree seeds are toxic to humans and to many animals, though careful roasting can detoxify the seeds when making the coffee substitute.


  Kentucky coffeetree bark is ridged, wood is used in cabinetry, fall color is yellow. Plant one or a group as specimens for the winterscape; the starkness is borne out by the Greek meaning of “gymoncladus” as “naked branch”.


Bark of Kentucky coffeetree


  Note: It seems inconceivable that I have no ready pictures in my files of the young and old seeds or of winter starkness, but I vow to correct that with images this winter and next spring and summer. Which also serves as a reminder that starting this year, BYGL is 24/7/12/365.