Ohio buckeye

Great Plains

Midwest

FAC - Facultative

Northcentral & Northeast

FAC - Facultative

Native to eastern and central United States, including Iowa; cultivated in Minnesota; may have escaped cultivation

Uncommon in Minnesota

Moist to mesic. Floodplain forests, mesic upland forests, streambanks and river banks. Full sun to part shade; moderately shade tolerant. Well-drained soil.

March to May

Greenish-yellow

20′ to 40′

This is an erect, small to medium sized, slow growing, moderately long lived, deciduous tree. It can be from 20′ to 60′ tall at maturity, though it is rarely more than 40′ in height and 24″ in diameter at breast height. In Minnesota it is usually no more than 30′ in height. It reaches full size in 60 to 80 years.

The trunk is short and much branched. In the forest the crown is oblong with ascending branches. When in the open the crown is spreading and broadly rounded.

The bark on young trees is thin, yellowish-brown, and smooth. As it ages it becomes dark grayish-brown and develops shallow fissures and corky, scaly plates. On mature trees the bark is brownish-gray, rough, and deeply furrowed with thick, scaly plates. Older bark has an alligator hide appearance and is often lighter gray.

The twigs are stout and reddish-brown to ashy gray. They have moderate-sized pith and a very disagreeable odor when broken. The leaf scars are large, broad, and shield-shaped. They have 3 bundle scars.

Terminal buds are reddish-brown, ½″ to ¾″ long, egg-shaped, and widest at the middle. They are covered with several pairs of triangular, overlapping scales that are ridged in the middle. The scales are covered with a powder and are not sticky. Lateral buds are similar but much smaller.

The leaves are deciduous, opposite, and pentagonal, kidney-shaped, or almost circular in outline. They are palmately divided into usually 5, rarely 7, leaflets. Each leaf is on a slender, 3″ to 6″ long, hairless leaf stalk (petiole). The petiole is about as long as the terminal leaflet. The leaves appear in the early spring. The earliest leaves are sometimes killed by a spring frost.

The leaflets are mostly inversely egg-shaped to elliptic, 2¾″ to 6¼ long, and 1¼″ to 2⅜″ wide, sometimes wider. They are tapered at the base and long-tapered to a point at the tip. The upper surface is yellowish-green, bright green, or dark green, and either hairless or minutely short-hairy along the veins. The lower surface is usually paler green, and is sparsely to densely covered with short and curly, sometimes with long and woolly, hairs, sometimes just along the veins. The margins are finely and irregularly toothed with sharp, forward pointing teeth. In autumn the leaves turn yellow and are among the first to drop.

The flowers appear after the leaves from March to May. Each tree bears both bisexual (perfect) and male (staminate) flowers. The inflorescence is an upright, pyramid-shaped, 4″ to 6″ long, branched cluster (panicle) at the end of smaller branches. The flowers near the base of the branches of the panicle are perfect, the remaining are staminate.

The flowers are ¾″ to 1¾″ long. They have 5 sepals, 4 petals, 7 stamens, and 1 style. The sepals are yellow to greenish-yellow and are fused at the base into a more or less bell-shaped tube (calyx) with 5 rounded lobes. The petals are greenish-yellow, ⅜″ to ¾″ long, and narrowed to a stalk-like base (clawed). The upper pair is more or less inversely lance-shaped and gradually tapered to the clawed base. They sometimes have an orangish or reddish central region and/or spots. The lower pair is shorter and broader, and is abruptly tapered to the claw-like base. The stamens protrude well beyond the corolla. They have white, ⅝″ to ⅞″ long stalks (filaments) and orange anthers. The style is white, unbranched, and longer than the stamens.

The fruit is a light brown to brown, egg-shaped, inversely egg-shaped, or nearly globular, ¾″ to 2¾″ long and wide capsule. The outer wall is leathery and warty and is usually covered with numerous spines that are shed as the fruit ages. Each fruit has 3 or 4 sections and contains usually 1, sometimes 2, rarely 3 or 4 seeds. The seeds (nuts) are not edible.

The fruit ripens in mid-fall and is dispersed by gravity from September to late October.

No records kept for non-native trees.

Horse chestnut (Aesculus hippocastanum) lealets at the tip are broadly rounded with a short, abrupt point. The flowers are white.

Sources: 2, 3, 4, 7, 29, 30.

Poisonous
All parts of the Ohio buckeye tree are toxic, including the nut, leaves, and bark. The toxicity is due to the presence of the glycoside aesculin, the saponin aescin, and possibly alkaloids.

Ohio buckeye in flower, May 2017, Freeborn County, MN

Fruit of an Ohio buckeye tree, Freeborn County, MN, July 2017

Leaves

Leaf

Infructescence

Fruit

Location: Owatonna, MN

Location: Freeborn County, MN

Ohio buckeye in flower

Location: Freeborn County, MN

Fruit of an Ohio buckeye tree