El Zaguán’s European Horse Chestnut Tree
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The horse chestnut tree in El Zaguán’s garden during the spring
By Ruthbeth Finerman, Santa Fe Extension Master Gardener
The horse chestnut is a deciduous flowering tree native to southeastern Europe. They can grow up to 75 feet tall and produce 12-inch long white or pink “petiole” flowers in spring. In fall it is covered in spiky green capsules or “fruit” that hold a brown nut-like seed or “conker”. Horse chestnuts (Aesculus hippocastanum) are named after the horseshoe shape of the leaves when they dry out. They are not related to chestnut trees (Catanea sativa), even though the leaves and fruits appear similar. Horse chestnut trees are at risk of extinction in Europe due to invasive insects, deforestation and climate change. Seeds from horse chestnuts were gathered in World War I and World War II to make acetone for cordite explosives. Medical researchers tested the tree but found it too toxic to provide any health benefits. Today, British children use the nuts for a game called “conkers”.
Of special note, the entire horse chestnut tree - including its bark, flowers, leaves, stems, and seeds - contains toxic alkaloids that are extremely poisonous if ingested by humans and animals!
El Zaguán had two horse chestnut trees, planted around 1880 by Maria Jesusita Johnson. One died in 2013 while the remaining tree is now over 140 years old, well past the species’ normal lifespan of 80-100 years. Moreover, half of the roots now extend beneath Canyon Road, where the street’s asphalt surface blocks water and nutrients from reaching and feeding the tree. Warming temperatures and drought conditions further stress the tree, so it should be treasured in its remaining years.
For more information visit:
Morton Arboretum: https://www.mortonarb.org/plant-and-protect/trees-and-plants/horse-chestnut/
National Institutes of Health: https://www.nccih.nih.gov/health/horse-chestnut
Historic UK: https://www.historic-uk.com/CultureUK/Conkers/
