Ohio buckeye (Aesculus glabra) is a commonly known species of tree. It is native to the midwestern region of the United States and is the state tree of Ohio. The buckeye seeds contain tannic acid, and are thus toxic to humans and cattle.
I. Appearance and Characteristics
Aesculus glabra, commonly known as Ohio buckeye, Texas buckeye, fetid buckeye, and horse chestnut is a species of tree in the soapberry family (Sapindaceae) native to North America.
Its natural range is primarily in the Midwestern and lower Great Plains regions of the United States, extending southeast into the geological Black Belt of Alabama and Mississippi. It is also found locally in the extreme southwest of Ontario, on Walpole Island in Lake St. Clair.
It is found in a variety of natural habitats, including streambanks, upland mesic forests, and along the margins of old fields. It is typically found in calcareous areas.
The name stems from Native Americans, who called the nut “hetuck”, which means “buck eye”. The markings of the nut resembled the eyes of a deer.
The leaves are palmately compound with five leaflets 8–16 cm (3–6+1⁄2 in) long and broad. The flowers are produced in panicles in spring, red, yellow to yellow-green, each flower 2–3 cm (3⁄4–1+1⁄4 in) long with the stamens longer than the petals (unlike the related yellow buckeye, where the stamens are shorter than the petals). The fruit is a round capsule 4–5 cm (1+1⁄2–2 in) diameter, containing one nut-like seed, 2–3 cm (3⁄4–1+1⁄4 in) in diameter, brown with a whitish basal scar.
The inedible seeds contain tannic acid and are poisonous to cattle and humans. The young foliage, shoots, and bark are also poisonous to some degree. However, Native Americans reportedly did eat buckeye fruit after boiling it to extract tannin.
Every part of ohio buckeye contains glycosides and saponins which cause severe illness. Consuming large amounts of this plant causes loss of coordination, muscle spasms, restlessness, depression, digestive upset, colic, vomiting, diarrhea, weakness, paralysis, and potentially, coma. Apparently, the nuts are sometimes roasted and eaten by humans by mistake, which is one major cause of poisoning in humans. The other is small children, who should all be kept away from this plant.
II. How to Grow and Care
Ohio buckeye is a hardy deciduous tree acknowledged for its resilience in varied environments, making it quite easy to care for. Key to Ohio buckeye’s health is ensuring it is planted in well-drained soil, as it does not tolerate waterlogged conditions. Another special care point is that Ohio buckeye prefers full sun to partial shade, thus positioning is important for optimal growth and flowering. Regular watering during dry periods will ensure a healthy ohio buckeye, but mature trees can tolerate some drought.
Sunlight
Ohio buckeye requires sunlight to grow. It can grow in partial shade to full sun. A position facing the sun is the most preferred, especially in the seedling stage, when sufficient sunlight is essential. In the shade, these plants are usually thin and prone to disease.
In hot summers, be wary of direct sunlight burning the plants. To avoid sunburn, put up shade nets for young trees. Large trees can be protected by painting their trunks white in late fall or early summer, or by covering the base of the trunk with organic mulch.
Temperature
Ohio buckeye prefers a moist growing environment with a temperature of 12 to 25 ℃. It can tolerate a low temperature of -40 ℃. Above 30 ℃, growth slows, and its leaves and trunk are sensitive to damage from high heat.
Watering
Adapted to temperate climates, Ohio buckeye thrives with moderate moisture and is native to regions where it experiences distinct seasonal changes. Its water habits reveal a preference for consistent but not excessive hydration, balancing its needs between drought resistance and a liking for well-drained soils. For optimal growth, Ohio buckeye requires watering once every 1-2 weeks. Typically grown outdoors due to its size and deciduous nature, ohio buckeye enters a period of dormancy in colder months, reducing its water requirements significantly during this time.
Soil
Ohio buckeye roots are deep and extensive, so its planting location requires a deep soil layer. It grows well in fertile, well-drained, slightly acidic to neutral (pH 5.5-7) sandy soil. Although it can also grow in light saline soil, its growth won’t be as good.
Fertilizing
For Ohio buckeye, apply balanced nutrition fertilizers in spring for robust growth, switching to high nitrogen fertilizers mid-season to support vigor and foliage. Optimal fertilization involves a slow-release formula every 6-8 weeks during the growing season, using instructions specific to product size. Promoting lush growth and bountiful seed production, fertilization enhances health and resilience. Limit applications as ohio buckeye matures and during dormancy. Apply at the canopy’s drip line, not near the trunk, and water thoroughly. Adjust practices with seasonal changes, lessening in autumn. Use personal protective equipment, avoid over-fertilization, and follow the label’s safety guidelines.
Pruning
Usually Ohio buckeye trees do not need pruning, because its natural crown is round and it is better to keep the original crown shape. Light pruning can be carried out after the fall of leaves: over-long branches can be shortened, over-dense branches can be thinned, and diseased or dry branches can be completely removed. This avoids the consumption of excess nutrients, allows more light to reach the plant’s interior, is conducive to its healthy growth, promotes the air circulation inside the plant, and effectively reduces disease.
Propagation
Ohio buckeye can be propagated through three different methods: hardwood cuttings, layering (air), and sowing seeds. The best time for propagation is in autumn or winter. Propagation difficulty is moderate, but if successful, signs include root formation and new growth. Key tips include selecting healthy parent plants and providing adequate moisture and light.
Transplanting
For Ohio buckeye, the prime time for transplanting is in the vernal awakening of early to mid-spring, ensuring root establishment before summer heat. Choose a spot with well-drained soil and dappled sunlight. If feasible, provide consistent moisture after relocation for seamless acclimatization.
Overwintering
Ohio buckeye thrives in its native Midwest U.S. climate, resiliently powering through cold winters. Known for its hardiness, the tree survives dropped temperatures by entering dormancy, shedding leaves to conserve resources. Gardeners must consider its natural winter-wellness, letting it rest and providing sufficient moisture. Spot check for winter pests or diseases that could hamper ohio buckeye’s re-blooming come spring.
III. Uses and Benefits
- Ornamental uses
Ohio buckeye is well-suited to planting in woodland area landscapes. It’s best kept away from streets, porches, and walkways as it releases quite a bit of leaf, twig, and fruit litter. This tree is valued for providing good shade, as well as the yellow and orange hues of its autumn leaves. Combine with Clethra alnifolia for splashes of color among its white spring flowers.
- Other uses
Aesculus glabra has little use as a timber tree due to its soft, light wood. Although occasionally seen in cultivation, the large, copiously produced fruits make it generally undesirable as a street tree. Extracts from A. glabra have shown anti-cancer properties.
Native American ethnobotany
The Lenape carry the nuts in their pockets for rheumatism, and an infusion of ground nuts is mixed with sweet oil or mutton tallow for earaches. They also grind the nuts and use them to poison fish in streams.
Native Americans blanched buckeye nuts, extracting the tannic acid for use in making leather. The nuts can also be dried, turning dark as they harden with exposure to the air, and strung into necklaces similar to those made from the kukui nut in Hawaii.
