Like the gleaming coat of a fine horse, the seeds of
our native buckeye and its European counterpart, the horse chestnut, shine-almost
glowing as they burst from their dull and oddly shaped capsule.
No hike in the woods in August or September would be
complete without collecting a few buckeyes to rub between your fingers or stick
in your pocket for good luck.
However, you should be aware that the seed pod and
seeds (what we call the buckeye) of these trees are poisonous if ingested.
Of the four buckeyes native to Kentucky, only two are
commonly encountered: Ohio buckeye, Aesculus glabra, and yellow buckeye,
Aesculus flava (A. octandra).
Ohio and yellow buckeyes
Ohio buckeye is the smaller of the two and ranges
in height from 20 to 40 feet. The palm-like compound leaves carry five leaflets
reaching an impressive 6 inches long. A wonderfully dense canopy results from
these large, dark-green leaves. The deep shade created below is an excellent
retreat from the heat of the day for man or wildlife.
Ohio buckeye is easy to identify in early spring
because it is one of the first trees to leaf out. In the fall it can have spectacular
yellow color but it is generally the first to concede to an extremely hot and
dry summer, dropping its leaves as early as late August. This characteristic
alone limits its popularity for use in the urban landscape environment.
The flowers are a pretty, greenish-yellow, or as
I like to describe them, not quite white. They emerge in early May just as the
leaves have finished unfolding and are 6-7 inches long and about 3 inches wide
at the base, tapering to the tip. It is very intriguing to walk upon a buckeye
as the flowers begin to open, rising slightly above the foliage-you are definitely
compelled to get a closer look.
Yellow buckeye, also found throughout Kentucky, is
quite similar to the Ohio buckeye but is larger, reaching heights of 60 to 75
feet. The flowers emerge at the same time and are roughly the same color, but
the seed capsule formed after flowering is smooth while the seed capsule of
Ohio buckeye is slightly prickly.
While most buckeyes are too large or too messy
for a small yard, we occasionally see them on large estates, parks, and in botanical
gardens or an arboretum. More frequently in cultivation you will see the European
horse chestnut, Aesculus hippocastanum, or red horse chestnut, Aesculus
x carnea. The foliage tends to be cleaner and holds on longer. The leaves,
also palm-like and compound, carry seven leaflets.
The flowers are what makes the horse chestnuts more
desirable. Much larger in size and much showier, the flowers of European horse
chestnut start out yellow and turn red and are an incredible 12 inches long.
The red horse chestnut’s flowers are a rosy red and up to 8 inches long. The
fruit capsule is very prickly and typically bears two seeds, while most buckeyes
bear only one seed per capsule.
My favorite buckeye has to be bottlebrush buckeye,
Aesculus parviflora. While this buckeye is not native to Kentucky it
is more suitable to the urban landscape. This large, sometimes-suckering shrub
grows to about 12 feet tall and 12 to 15 feet wide. What makes this plant great
is that it will grow in sun or shade. It tends to sucker less in a sunny site.
It is also more tolerant of dry soils and more disease-resistant than most buckeyes,
holding onto its foliage later in the season, giving you great yellow color
The flowers are white and rise above the foliage,
making an absolutely stunning show. They are also long, as with most buckeyes,
but are slender from base to tip resembling a bottle scrub brush. The flowers
form and begin to elongate in late May, reaching peak color about June 15.
Least poisonous buckeye
In our area bottlebrush buckeye blooms beautifully
but rarely sets fruit, which is consistent throughout the north. In most cases
only 2 or 3 capsules are formed per mature plant. It can be disappointing, but
in many cases this serves as an advantage in the urban landscape since all buckeyes
are poisonous. The poor fruit set allows us to plant bottlebrush buckeye in
areas where other buckeyes would be too dangerous, such as schoolyards, around
a farmhouse, or even in our own back yards.
The beauty and the danger of the buckeye remind us
to choose our plants wisely. We often make quick decisions and are lured to
purchase a plant without having all the facts. I encourage you to take the time
for a little research, consult a professional, or stop by your local library
and get to know the plants you fall in love with, before choosing to plant them
in your garden.