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Season of Trees: Meet the 'Character' among MN Trees!

The Minnesota Landscape Arboretum is all about trees. This month, we’d like to introduce you to a native tree that really relies on human intervention to spread itself around. With giant leaves and cool rattling seed pods, Kentucky coffeetree is quite the character of the tree world!

Kentucky coffeetree

Kentucky coffeetree (Gymnocladus dioicus) is a medium-size, slow- to medium-growing deciduous tree, native from Minnesota to Oklahoma, and east to New York and Tennessee.
In the wild, it is often found in deep ravines and moist slopes.  

In Minnesota, its presence is considered rare if it is not intentionally planted.

What is the Kentucky coffeetree?

Here's some characteristics that may help you identify this tree: 
  • Deciduous, leaves drop in fall
  • Dioecious - male trees produce no seed pods, female trees do
  • Height: 60 to 75 feet; Width: 40 to 50 feet
  • Has an upright, unusual form as limbs can be spread far apart with irregular branching - all individual trees look quite unique
  • Bark: gray to dark brown, plated and ridged; younger branches share this scaled look
  • Leaves: bipinnately compound with 3 to 7 pairs of pinnae, each with 6-14 leaflets; leaves are up to 36 inches long and 24 inches wide
  • Buds: no terminals, but laterals are small, bronze, and partially sunken
  • Flowers: as part of the bean family, trees produce 8 to 12 inch long panicles of 1 inch fragrant white flowers in late-spring
  • Fruit: reddish-brown to black 5 to 10 inch long pods, containing several rock-like seeds

Best growing conditions

As a landscape tree, it exhibits an unusual, open branch form.The leaves are bipinnately compound, meaning each leaf is up to 36 inches long and 24 inches wide, with dozens of leaflets. It has a nice yellow fall color and winter interest with its branching and persistent pods.
  • Hardiness zone: 3 to 8
  • Full sun
  • Tolerates drought once established
  • Tolerates some salt, and pollutants
  • Recommended soil properties include a soil pH that's versatile, tolerant of chalk (limestone); Prefers rich, moist soil. Have your soil tested by the U of M Soil Testing Lab.
During winter months, the scaly, ridged bark generates interest, as do the reddish-brown seed pods that persist until spring.

Each seed pod contains a few hard seeds that need to be scarified or nicked before they will germinate. As such, natural propagation today is mainly through roots sending out sucker sprouts to form small colonies.

Where did its name come from?

As its name implies, early settlers to the region brewed the seeds as a coffee alternative. As the taste was not preferred, it was usually a last resort. Native Americans also used the seeds as dice and for jewelry.
While its structure is good for nesting birds, parts of the tree are toxic and are not a good food source for wildlife.

Common problems

No serious insect or disease issues. As parts of the tree are toxic, removal of seed pods and leaves from areas with grazing animals is recommended. Any plant parts that fall into standing water could make the water undrinkable for wildlife. Careful location selection is recommended.

Visit What's wrong with my plant? - Kentucky coffeetree for a list of the most common pest problems in Minnesota.

Cultivated varieties for Minnesota

Cultivated varieties are selected for size, color, and performance in Minnesota. We recommend buying from local nurseries, as Minnesota-grown plants are already adapted to our climate and soils, require less transportation and fuel costs, and are unlikely to introduce or spread invasive species from other parts of the country.
  • 'Espresso' - Male (no seeds), more of an upward form, 50 feet tall and 35 feet wide
  • 'True North' - University of Minnesota introduction, male (no seeds) upright and narrow, 50-70 feet tall and 25-30 feet wide.
The above varieties are listed in the Plant Information Online database, which offers plant and seed sources throughout North America.

Our favorite Kentucky coffeetree at the Arb

The Minnesota Landscape Arboretum has a dwarf form of Kentucky coffeetree in our Dwarf Conifer Collection, just off the path leading to the lower waterfall area. Though referenced in Michael Dirr’s Manual of Woody Landscape Plants, it has not been propagated, making it truly unique. You should visit to enjoy it!

Kentucky coffeetree is on our Interactive Tree Trek map. To find one, click the layers icon in the top right and add "Tree Trek." The map will show you where to go, and give you a little info to take with you!

Author: Erin Buchholtz, Integrated Pest Management Specialist, Minnesota Landscape Arboretum

Editor’s note: This article is the second in a series the Y&G News called “Season of Trees.”  Every month, we’ll tell you all about a specific tree, what varieties do well in Minnesota and how to grow them.

In 2020, the Minnesota Landscape Arboretum celebrates the “Season of Trees: Returning to our Roots” which will highlight the beauty and benefits of trees in our communities.
Erin Buchholtz, Mn Landscape Arboretum

Our guest writer for this series is Erin Buchholz from the Arboretum. Erin earned her bachelor's degree in Horticulture from the University of Minnesota. She has worked in nonprofits and public gardens for over 15 years, and worked as an elementary school teacher for five years while earning her master's degree in education.  

She has returned to her love of connecting people to plants as the IPM (Integrated Pest Management) Specialist at the Minnesota Landscape Arboretum. Combining horticulture with education, she teaches staff and visitors how to use IPM to keep plants (and people) healthy.

  --Gail Hudson, Y& G News Editor

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