Each summer, I live with my parents in Great Barrington, Massachusetts in a large Victorian house built in the 1880s, while working at Tanglewood, the summer home of the Boston Symphony Orchestra. I sleep in the back of the house in a room that is uninhabitable in the winter months because the radiators were melted for metal during WWII. The eastern window faces a distant view of East Mountain over three towering spruce trees. The northern window looks directly into the drooping branches of a large horse chestnut tree, the site of a long since removed treehouse.
Aesculus hippocastanum, the horse chestnut, is a member of the Sapindaceae, or soapberry family, a giant flowering specimen that originally took root on the Balkan Peninsula, in the remote Pindus Mountains of Greece. There are now horse chestnuts in parks, gardens, and estates, although rarely wooded areas, across Europe and North America including Canada. The tree’s range is fascinating for a plant which drops mildly poisonous seeds and whose wood is poorly suited for either construction or burning.
The earliest references to the tree in Western Europe crop up in Vienna in the late 16th century. While heading up the royal garden of Maximlian II, botanist Carolus Clusius was gifted a small tree from David Ungnand, the Imperial Ambassador to the Emperor of the Turks. Eventually, the tree found its way to America, as a popular ornamental tree. E.H. Wilson, a plant collector and eventually the Keeper of the Arnold Arboretum in the early 1900’s wrote “if a census of opinion were taken as to which is the most handsome exotic flowering tree in the eastern part of the United States there is little doubt but that it would be overwhelmingly in favor of the Horse chestnut.” I suspect that my parents’ horse chestnut sprouted amidst this fervor of botanical enthusiasm.
Although my family laid down the hops and barley generations ago, our surname is Brewer. Horse chestnuts are integral to Bavarian beer gardens. Specimens of the tree dangle their branches over each of the 172 beer gardens in Munich. At first, the tradition was practical. Beer gardens burst onto the social scene in Germany in the early 1700s and brewers needed to keep large stores of ingredients in cool moist spaces. So they built underground basements and topped these with groves of horse chestnut trees, whose shade helped to maintain a constant temperature. The tree’s palmate leaves are among the first to bud in the spring, and its spreading branches cast dark cooling shadows. Each spring, the horse chestnut produces towering flowers with cascading red, white, and yellow blossoms. The tree’s dramatic May display aligns with the start of the Bavarian beer garden season, serving as an organic marketing campaign.
The horse chestnut derives its name from Turkey, where the seeds, called conkers, were reportedly fed to horses suffering from respiratory problems. More recently, the aescin in conkers has been successful in treating chronic venous insufficiency (CVI), varicose veins, and hemorrhoids. The dosages must be small, because the conker is actually poisonous to humans, horses, and most other animals, with deer and wild boar among the notable exceptions. Conkers, which are protected by a spiky husk, are also the crucial pieces in a British children’s game of the same name which originated on the Isle of Man in the 1800s.
So the horse chestnut is a colorful umbrella for beer gardens, a semi-poisonous seasonal toy for children, an alternative medicine for varicose veins, and a 100-foot-tall May boquet. The tree is also a supporting character across literature. It is said that Lewis Carroll first spotted the shadowy Cheshire Cat in the branches of a horse chestnut in the Deanery Garden in Oxford. Perhaps most famously, “Under the spreading chestnut tree the village smithy stands,” in Henry Wadsworth Longfellow’s ode to the common man, The Village Blacksmith. This horse chestnut, which once stood on Brattle Street in Cambridge, Massachusetts, was cut down as the street was widened in 1876. The children of Cambridge presented Longfellow with a chair made of the tree’s remains, which is still on display at the Longfellow House.
Three-quarters of a century later, a horse chestnut in Amsterdam helped sustain Anne Frank during the Holocaust. A horse chestnut tree and a small patch of sky were some of Anne’s only visible connections with the outside world. In her diary, Anne writes that she and her friend Peter, “looked out at the blue sky, the bare chestnut tree glistening with dew, the seagulls and other birds glinting with silver as they swooped through the air, and we were so moved and entranced that we couldn't speak...As long as this exists, I thought, and I may live to see it, this sunshine, the cloudless skies, as long as this lasts, how can I be sad?”
In 2010, the 170-year-old Anne Frank Tree, which had been weakened by fungus and moth infestations for decades, was toppled by a strong wind. In anticipation of the tree’s demise, The Anne Frank House collected dozens of conkers and germinated them. Saplings originating from the tree were donated to schools and organizations in cities around the world to propagate the legacy of Anne Frank.
In the United States, The Sapling Project, housed by the New York-based Anne Frank Center for Mutual Respect, was awarded eleven saplings to be distributed around the country. Aliya Finkel, a young student at the Waltham-based Gann Academy encouraged the city of Boston to apply for one of these trees, and in 2013 a sapling was planted in the Boston Common. Sadly, the sapling succumbed to disease, and despite the best efforts of horticulturists and arborists at the Boston Parks and Recreation Department, the tree did not survive its first winter in the city. I’ve reached out to the Anne Frank Center For Mutual Respect to see if one of the ten other U.S. locations might consider sharing a cutting from their trees for cultivation in Boston but have yet to hear back.
Each time the horse chestnut migrates, whether from the Pindus Mountains to Europe, or across the Atlantic Ocean to the United States, it is because a human has become enthralled with this majestic flowering species. Looking out into the tangled branches of my parent’s spreading horse chestnut tree, I wonder who dropped the conker that created decades of shade for my family’s picnics, a gorgeous floral backdrop for our spring days, and branches for a treehouse where I spent hours engrossed by books. Where did the seed come from and why did they plant it?