Gymnocladus dioicus

Tuesday September 4, 2018

In 2004, the Brenton Arboretum contemplated developing a Nationally Accredited Plant Collection as the area of research had been a part of the mission since its founding by Mr. and Mrs, Brenton in 1997.  The Kentucky coffeetree was not currently a PCN collection and definitely under-utilized in the urban landscape.  Its adaptability to urban conditions and drought, with no serious insect or disease problems, would make it a likely candidate among diverse tree genera to replace ash trees affected by the Emerald Ash Borer as well as oaks being affected by oak wilt within our cities.  With Iowa being within the core part of the species native range, it was also well suited for planting and thriving in central Iowa.  A meeting with Dr. Mark Widrlechner, the PCN’s Iowa Recruiter employed at the National Plant Germplasm System (NPGS) genebank in Ames, Iowa, solidified the decision to work with the Kentucky coffeetree and determined seed samples of coffeetree would be a welcomed addition to the gene banks current holdings.  Thus began a long term relationship between the Andy Schmitz, Director of Horticulture at the Brenton Arboretum and NPGS horticulturist, Jeff Carstens.

Since 2008, twelve joint seed collecting trips have been conducted to acquire seed from high-quality wild populations across the species native range to create an ex situ living plant and seed collection at the Brenton Arboretum and NPGS, respectively.  These expeditions have covered 17 states traveling over 25,000 miles and all while spending 75 days on the road.  The years of explorations have resulted in the creation of an impressive comprehensive collection of 131 tree accessions and 88 seed accessions with each accession being from a different wild location.

The first wild collected trees were planted in 2013 in informal groupings where each tree has the potential to reach its mature size while forming an intertwined canopy.  Seed collecting and planting are ongoing to acquire germplasm representing unique habitats and outlying populations.

The Brenton Arboretums focus since the beginning has been in the area of conserving genetic diversity. However, the collection has expand to showcasing newly introduced and preserving historical cultivars of Gymnocladus with attempting to obtain them from the ortet to confirm the authenticity.

To read more about the collecting endeavors,

To view and search holdings of to Gymnocladus dioicus which are available for research, evaluation and breeding, please visit the Germplasm Resources Information Network (GRIN) at