Ohio Buckeye is a tree with a rounded crown that can grow to 70 feet in height.
Bark is smooth on young wood, gray, then develops corky patches, eventually becoming rough and dark gray.
Twigs are thick with a shield shaped leaf scar resembling a monkey face, opposite lateral buds and much larger terminal buds. Buds are orangish brown and not sticky, light colored with fine hair on the scales. In Spring the buds swell and elongate with the scales turning pinkish. Young new twigs are green, turning reddish and finally gray after the 2nd or 3rd year. Young twigs have light colored lenticles.
The leaves are opposite and palmately compound, with 5 to 7 leaflets that are elliptical and unevenly saw-toothed, dark green smooth surface above and paler below. Crushed leaves give off an unpleasant odor.
The inflorescence is an upright terminal panicle at the end of new growth twigs.
The flowers are bisexual, individually stalked, with a long yellow to greenish-yellow calyx tube that has 5 lobes and fine hair. There are 4 petals, creamy color to pale yellow which also have fine hair on their edges. The two upper petals have a reddish patch near their base. The two lateral petals tend to spread outwards and have a smaller reddish patch. All 4 petals have clawed bases (the forward parts are larger). There are 7 stamens with orange-red anthers and a style.
The fruit is a round (1 to 2 inch) initially spiny capsule that contains one to three dark brown nuts that mature in the fall. Capsules are rather thin walled and easily opened. The seeds are poisonous to humans (but not squirrels) and will readily produce new trees if protected from squirrels. Nuts readily germinate and many young trees may result.
Habitat: Ohio Buckeye is a tree of the mixed hardwood forest, growing in moist to somewhat dry soils. Young trees can survive for a time under the canopy but for maturity must have sunlight. These trees are fast growers and in groups, may dominate an area.
Names: The genus Aesculus is the Latin name for a nut-bearing oak but Linnaeus applied it to a group of Horse Chestnuts. The species glabra, means 'without hairs' and is used here for the stems and leaves that are without hair. The author name for the plant classification - ‘Willd.’ is for Carl Ludwig Willdenow (1765-1812), German botanist, a founder of the study of the geographic distribution of plants. He was director and curator of the Botanic Garden of Berlin. The alternate common name of "fetid buckeye" refers to an unpleasant odor of crushed leaves and twigs. This tree has recently been reclassified by botanists into the Sapindaceae family which includes all the maples. It used to be in the Horse Chestnut family (Hippocastanaceae) and some reference sites will still list it there.
Above: 1st photo - Ohio Buckeye mature bark. 2nd photo - In open spaces the tree develops a rounded crown. 3rd photo - Flower Buds of early May
Below: 2nd photo - Flowers have a yellow to greenish-yellow calyx tube that has 5 lobes and fine hair. 3rd photo - Flowers have 4 petals, creamy color to pale yellow which also have fine hair on their edges. The two upper petals have a reddish patch near their base. The two lateral petals tend to spread outwards and have a smaller reddish patch. All 4 petals have clawed bases (meaning the forward parts are larger and the bases are narrowed). There are 7 stamens with orange-red anthers and a style.
Above and below: Above 1st photo and below 1st photo - Twigs have shield-shaped leaf scars resembling a monkey face; lateral buds are opposite and orangish-brown. Above 2nd photo - in the Spring the buds and scales elongate and the scales take on a beautiful pink color. They then fold back and still pink, enlarge while the leaves unfold.
Below: Fruit Development: 2nd photo - new seed capsules emerging from the residue of the flower stalk. 3rd photo - Mid-period shape of the capsule.
Below: 1st photo - The maturing seed capsules. 2nd photo - Individual seeds.
Below: The compound leaf.
Notes: Ohio Buckeye is the state tree of Ohio. Minnesota is north of it's normal distribution, although a native population was reported in Wabasha County; otherwise it is an introduced tree and does well in the Garden and elsewhere in the Metro area. It does so well that a number of them have had to be removed from the Woodland Garden at Eloise Butler as they were crowding out more native species. This is the only species of Aesculus that will be found in Minnesota other than landscape plantings which may contain newer cultivars. There are however, a number of other species of Aesculus found in North America.
Eloise Butler recorded planting the tree in April 1911, sourced from Strand's Nursery in Taylor's Falls, MN. She planted more in 1916. Martha Crone noted in her log planting this tree in 1934, 10 more in 1939, more in 1949; those on Geranium Path are of good size and have recently (2015) been thinned out due to their prolific growth. A younger but very nice specimen is just off the front porch of the Martha Crone Visitors Shelter.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"