Kentucky Coffeetree: Watching Seed Pods

Since August, I have been checking regularly two Kentucky Coffeetrees that grow in Detroit’s Eliza Howell Park, paying them much more attention than I have in other years. My main interest has been the developing seed pods.

These pictures were taken in August.

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Kentucky Coffeetree is a tree native to, though not very common in, parts of the mid-west. Southern Michigan is at the northern end of its original range. It is now sold by nurseries and used as a landscaping tree. The size and location of the Eliza Howell trees suggest that they were planted here long after the park was established. They are both female trees, producing seeds.

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The seeds (beans) of the tree have been used – roasted – as a food in some Native American cultures and the Meskwaki (Fox) are said to have ground them for use in a hot beverage. Early European colonists also tried it as a “coffee” as well. (Unroasted pods and seeds are reportedly toxic.)

The seeds mature slowly. When the leaves began to turn in October, the pods were darker in color, but remained firmly attached.

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The pods vary in length, most about 4 or 5 inches long, much shorter but thicker than the pods of the Honey Locus tree, often seen on the ground at this time of the year. I placed the two together for comparison.

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Now, in early November, the Coffeetree leaves are down. But the seeds remain firmly on the tree; I have not yet found a single one that has fallen on its own. (I picked those that I have examined.)

This picture was taken this week.

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The pods are not yet as tough as they will get and the seeds, though considerably changed since August, are not yet fully mature.

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I sometimes refer to my visits to Eliza Howell as “doing research.” It sounds more serious than “going for a walk.” One of my current research questions is: “When will the Kentucky Coffeetree seed pods fall?” My hypothesis is that it will not be for at least another month.

It’s an exciting life I lead – watching seeds mature!