Tree of the Month November 2021: Ohio Buckeye Aesculus Glabra

By Martin (Mort) Schmidt, for Simply Living

Ohio Buckeye Tree in Bloom Photo by Mort Schmidt

The Ohio State University’s famous football coach, Woody Hayes, described the Buckeye as “a worthless nut”. And so it is. Nor does the wood have much value. But in November, as we’re winding up the football season, what better tree to honor than the State Tree of Ohio, Ohio Buckeye? Aesculus glabra, aka Stinking Buckeye or Fetid Buckeye, is native to Ohio, and not surprisingly, our most common Buckeye. Its natural range forms a band stretching from Ohio, west to Missouri, and from there, southward to northeastern Texas. Ohio Buckeye is especially common in moist soil along stream banks.

Ohio Buckeye is one of the few Ohio trees with opposite, compound leaves. The opposite trees are those with leaves and branches arranged directly across from one another, as shown in the figure below. The most common trees with the opposite arrangement make up the MADBuck group: Maple, Ash, Dogwood, and BUCKeye. Buckeyes also have compound leaves, meaning that multiple leaflets share a stem, in the case of Ohio Buckeyes, usually five leaflets. Pinnately compound leaves are attached to the stem at multiple points, whereas palmately compound leaves, including Buckeyes, are attached to the stem at a single point. Besides Buckeyes, the only Ohio trees with opposite, palmately compound leaves are American Bladdernuts, with leaflets in groups of three. So – a tree with opposite, palmately compound leaves with five leaflets is a Buckeye. The two Ohio natives, Ohio Buckeye and Yellow Buckeye, Aesculus flava, have similar leaves, but Ohio Buckeye leaves emit a foul odor when crushed. (Make of it what you will, but I can’t smell the difference).
The leaflets of both species are ovate and widest near the middle, so they’re hard to distinguish using leaves. Because Buckeyes are among the first trees to lose their leaves in autumn, you might have to wait until spring to see them.

Left – Alternate vs Opposite. Center – Pinnate vs Palmate. Right – Ohio Buckeye Leaves & Fruit. Photos by Mort Schmidt.

The Ohio Buckeye typically reaches a height of less than 50 feet, and a diameter of less than 2 feet. The bark is distinctive. It is typically light gray and scaly, but lacking grooves, plates, or other distinctive patterns. To me, the bark resembles cigarette ash. In winter, Buckeyes have large orange buds with clearly visible scales. In the spring they have showy panicles of creamy white
flowers, also with a (supposedly) disagreeable odor. According to Lucy Braun’s classic The Woody Plants of Ohio, Yellow Buckeye, aka Sweet Buckeye, is largely limited to Southern Ohio, but it hybridizes with Ohio Buckeye. Perhaps the lack of odor indicates that I’m smelling hybrids. David Allen Sibley’s The Sibley Guide to Trees, a favorite books for tree identification, says that, “Because of hybridization, identification of Buckeyes can often be challenging”.

Left – Ohio Buckeye Bark. Center – Ohio Buckeye Buds. Notice opposite placement of lateral buds. Right – Ohio Buckeye Flowers. Photos by Mort Schmidt.

Like most trees with compound leaves, Buckeyes have a large leaf scar. The Ohio Buckeye has a somewhat C-shaped scar, whereas the Yellow Buckeye has an elongated scar. Remember that The Ohio State Buckeyes play in Columbus, with a capital C.

Left – Ohio Buckeye Leaf Scar. Right – Yellow Buckeye Leaf Scar. Photos by Mort Schmidt

Of course the most distinctive trait of Buckeyes are the large brown fruits with a light brown circular spot. One or several Buckeye nuts are surrounded by a green leathery husk. The Ohio Buckeye husk is bumpy, while the Yellow Buckeye husk is smooth. Of course, The Ohio State University mascot, Brutus Buckeye, is an Ohio Buckeye, so remember Bumpy Brutus Buckeye is
the Ohio variety. The native Buckeyes can also be distinguished by height. Ohio Buckeyes are generally less than 50 feet high, while yellow buckeyes reach heights of 100 feet. There are approximately 20 species of Buckeyes – including some from elsewhere in North America and Eurasia. Many of the others are referred to as Horse Chestnuts, but they are also Buckeyes and belong to the same genus, Aesculus. Horse Chestnuts can generally be distinguished
from our native Buckeyes by having one or more of the following features:
● More than five leaflets,
● Differently shaped leaflets, some of them widest near the tips,
● Differently colored flowers, often pink or red,
● Different blooming seasons,
● Shrubby growth habit,
● Presence in landscaping but not forests.

Left – Yellow Buckeye Fruit. Center – Common Horse Chestnut Flowers & Leaves. Right – Red Buckeye Flowers. Photos by Mort Schmidt.

Ohio Buckeye is one of the softer woods in Ohio with a Janka hardness of 770 lbf and a Specific Gravity of 0.52 (the SG of water is 1.0). Of the roughly 70 Ohio trees for which I collected hardness data, Walnut’s in the middle, with a hardness of 1,010 lbf and a SG of 0.55. Even so, Ohio Buckeye is more than twice as hard as Yellow Buckeye. Ohio Buckeye wood is light in color, and like most light woods, has poor rot resistance. It is hard enough for boxes and pallets, and it’s occasionally used for furniture. Its light color and low
softness make it suitable for paper pulp. Buckeye is somewhat difficult to split, which together with its low density (and therefore low fuel value) make it a poor choice for firewood. Historically Buckeye was sometimes hollowed out to make cradles and troughs that resisted splitting. Buckeye and Horse Chestnut were also used for artificial limbs. While not as strong as many woods, they were strong enough, and the trend of increased weight with greater strength made harder woods less desirable.

Buckeyes are high in tannic acid and Native Americans sometimes boiled them to extract tanning solutions. Buckeyes also contain aesculin, which is bitter and poisonous. The nuts were therefore sometimes pulverized and made into a book-binding paste that repelled insects. They were also sometimes crushed and thrown into lakes and streams to stun fish, making them easy to collect for
consumption.

Buckeyes are poisonous to humans, but they can be made edible with prolonged soaking or boiling in water, as the Indians sometimes did. I don’t recommend trying it. Shoots and twigs have been known to poison livestock.

Some believe Buckeyes have medicinal value. The pioneers often carried Buckeye nuts to relieve joint ailments, but it’s doubtful that they had any medicinal value while still in their coverings. According to Rebecca Rupp’s Red Oaks and Black Birches, the Science and Lore of Trees, Native Americans pulverized Buckeye nuts and mixed them with grease to relieve hemorrhoids. Rupp also indicates that Buckeyes were once regarded as a cure for syphilis. Fred Hageneder’s The Meaning of Trees includes the reduction of pain and swelling in the list of Buckeye’s medicinal properties.

According to Rupp, Buckeyes are eaten by some wildlife, including squirrels, but according to Donald Culross Peattie’s A Natural History of Trees of Eastern and Central North America, “Squirrels are not known to eat them”. Whatever the case, Buckeyes are not squirrels’ preferred food, and despite their differences, both books make informative and enjoyable reading. (The Sibley
Guide agrees with Rupp on this count).

The association between Buckeyes and the State of Ohio goes back many decades. Red Oaks and Black Birches describes how William Henry Harrison handed out Buckeye walking sticks during his 1840 presidential campaign. Interestingly, Rupp also reports that the largest Ohio Buckeye is in Kentucky, while the largest Kentucky Coffee Tree is in Ohio (or at least they were in 1991).
Despite its limited worth, I celebrate our state tree by proudly shouting, “Go, Buckeyes!”