The sign by a Bob Evans restaurant in West Virginia proudly touted their “Buckeye Hotcakes.” Sounds tasty—presuming that there not made with actual buckeyes, that is. Buckeyes are poisonous. You’d have to think that they meant buckwheat, Fagopyrum esculentum, a crop plant that is indeed edible and occasionally added to pancakes.
Buckeyes are the large brown toxic fruits of the various trees and shrubs in the genus Aesculus. In North America, the plants themselves are also referred to as buckeyes, while in Europe the common name in English is horsechestnut. In yet another case of confusing nomenclature, horsechestnut trees are not related to the true chestnuts, the genus Castanea, trees that produce edible nuts.
Depending on your authority, between 13 and 19—or even up to 25—species of Aesculus populate the northern hemisphere. As always, taxonomists argue over weather a certain buckeye might be a true species, or perhaps merely a variety. To muddy matters further, many Aesculus species freely hybridize. Nomenclature aside, a distinguishing feature of all members of the genus is their palmately compound leaves. No other trees or shrubs native to our part of the world have similar leaves. Another common attribute of all Aesculus species: a tall upright inflorescence, known as a panicle, incorporating a few dozen flowers.
Several Aesculus species have ornamental qualities, either as garden additions or as plants that can be enjoyed in the wild. Native to the Balkans but widely planted throughout Europe and the northern U.S., the Common Horsechestnut (A. hippocastanum) makes a stunning statement when covered in white flowers, each with a reddish blotch at the base of the petals.
Following flowering, things start to go downhill, however. A host of insects and diseases can attack the foliage, leaving an unsightly plant by mid-summer. For this reason, this species is no longer commonly planted in the U.S. It’s not particularly fond of our summers, as well.
The Ohio Buckeye (A. glabra) provided a nickname to that state via William Henry Harrison’s presidential campaign, portraying him as living in a cabin made of buckeye logs. A medium-sized tree native to the Midwest and on into Texas, the greenish-yellow flowers tend to get lost in the foliage a bit. Like many buckeyes, it’s one of the first trees to leaf out in the spring, and also one of the first to lose its leaves, often by late August. It’s best enjoyed in its native habitats.
The largest American species, Yellow Buckeye (A. flava, formerly known as A. octandra) is native to the southern and central Appalachians, as well as adjoining areas of the Piedmont and Cumberland Plateau. In May, yellowish flowers adorn trees up to 90’ tall in the mountains of Virginia. Yellow Buckeye seems less troubled by the foliar diseases that afflict so many of the Aesculus, although I’ve noticed trees that were showing “fall” color/leaf blotch in August. An interesting tidbit about its native range: in Virginia it extends as far north and east as Augusta, Nelson and Buckingham Counties, but it never makes it to Albemarle.
Two smaller buckeye trees inhabit the understory of North American forests. Found from southern Virginia, south to Alabama and across to Tennessee, Painted Buckeye (A. sylvatica) generally grows to 10’ to 15’. Flowers are typically yellow, but occasionally show a bit of red. Of similar size, Red Buckeye (A. pavia) has bright red flowers, as the name suggests. Its native range extends from southern Virginia to Texas.
Despite their small stature, both of these buckeyes typically have a single stem (or trunk) and are trees rather than multi-stemmed shrubs. They prefer ample moisture and high shade, especially in the afternoon. Even given ideal growing conditions, they tend to drop their foliage in late summer. Don’t plant them as a focal point in wide open, sunny, windy conditions.
Owing to its bright red flowers, Red Buckeye has been crossed with other species, particularly A. hippocastanum. The resultant hybrid, Aesculus x carnea or Red Horsechestnut is commonly planted in England. Among several cultivars of this hybrid, ‘Briotii’ has deeper red flowers in larger panicles. ‘Fort McNair’ is known for good foliage and pink flowers with yellow throats. Although all these hybrids and cultivars are less susceptible to leaf blotch and mildew than the parent A. hippocastanum, the diseases may still strike, especially in the South. It’s all too easy for a buckeye to knock your socks off in May, then disappoint in August.
With all the caveats regarding Aesculus mentioned above, is there one that’s less troublesome and better suited to general garden conditions? Consider the Bottlebrush Buckeye (A. parviflora), a spectacular plant in flower that often develops good fall color. Native to Alabama, as well as small areas of Georgia and South Carolina, it’s hardy to at least Zone 5.
Bottlebrush Buckeye earns its name by virtue of its foot-long upright inflorescence, generally in bloom in early summer. A couple of cultivars of Bottlebrush Buckeye exist: Aesculus parviflora variety serotina flowers a couple of weeks later, but is otherwise similar. The same plant with the name ‘Rogers’ appended also provides later bloom, but the major distinguishing characteristic is the size of the inflorescence, up to 30 inches long. Owing to their great length, they arch over, rather than standing up straight, as on the species. High overhead shade, humus-rich soil and ample water are required for Bottlebrush to thrive in the South.
Even with this plant, there is one caveat: size. Once established, Aesculus parviflora can reach a height of 10’ to 12’ feet, with a similar spread. In fact, due its suckering nature, the spread is virtually boundless, so give it plenty of room. Don’t tuck into some tiny space right by your house.
And a final reiteration: buckeyes are poisonous. I wouldn’t recommend them if you have kids that put everything in their mouths, or dogs that that have omnivorous tendencies.