The horse chestnut, (Aesculus hippocastanum) should not be confused with the Ohio buckeye or the sweet chestnut, although the three species are very similar. The horse chestnut is a popular shade tree in the United States that dates back to the time of the Colonies. It has no useful purpose other than ornamental decoration and as a shade tree.
The horse chestnut is native to the mountains of Greece and Albania. It has been grown in Europe for several centuries; early mentions of the horse chestnut in England date back to 1580. It was later brought to the New World by Colonists. It has been spread by gardeners and landscapers throughout the United States ever since.
The horse chestnut is a tall tree that has a rounded oval shape. It can reach up to 80 feet tall but usually stays around 50 feet. The spread is usually about 40 to 50 feet wide. The leaves are compound, made from five to seven oval leaflets that are joined in the center. In spring it puts on a display of white flowers that grow in clusters on 5- to 12-inch-long spikes. It produces a nut that is 2 inches in diameter, encased in a spiny shell.
Horse chestnut trees grow in full sun in USDA zones 3 through 7. They prefer a rich well-draining soil that remains moist. They cannot tolerate soils that remain dry for long periods or hot weather. Once they are established, they tend to be relatively care free.
Horse chestnut trees are often used as a large shade or specimen trees in open areas such as public parks and golf courses. This tree is too large for many home landscapes and should only be used in larger yards. Some people take horse chestnut extract as an herbal remedy for varicose veins. The ancient Turks were said to have used it to make cough medicine for horses.
In high heat the leaves can burn and fall off. Often the plant completely looses its leaves from heat before fall. In wet areas powdery mildew can be an issue. The wood can be very brittle and is subject to breaking in strong storms. The nuts can become a big messy problem. They are hard and said to be poisonous, causing gastrointestinal problems when eaten by livestock. They litter sidewalks and streets and can cause a hazard to pedestrians who slip on them. The cultivar 'Baumannii' does not produce nuts and as a bonus has double flowers.