By Jesse Batty
As you’ve been walking through your neighborhood this fall, you may have noticed chestnuts on the sidewalk and thought “Boy, those sure would taste good. Maybe roasted on an open fire?”
Be careful! What you think are chestnuts are most likely Horse-chestnuts (Aesculus hippocastanum). Despite having beautiful spring flowers, these trees have horrible tasting nuts, toxic to humans due to a toxin called aesculin. This toxin is found in the leaves, flowers and twigs of the Horse-Chestnut. While a full-grown adult wouldn’t die unless a LOT of nuts were consumed, children can become much sicker at much lower doses.
That said, even amongst all the Horse-chestnuts in our city streets, you can still find a few European, Japanese, & Chinese Chestnuts (Castanea sativa, C. crenata, C. mollissima) which are indeed edible. The main difference is that the Horse-chestnut has a palmately compound leaf and a spiky armor like husk around the nut, whereas the Chestnut has a simple serrated leaf with a spiky sea urchin like husk around the nut.
Unfortunately, the most delicious chestnut of all, the American Chestnuts (Castanea dentata), were largely wiped out by a fungal blight, although two prominent American chestnuts remain along Leif Erickson Trail in Portland and in Fort Vancouver in Vancouver. So don’t eat those Horse-chestnuts! Keep your eyes peeled for the true chestnuts and consider yourself lucky if you get to eat an American chestnut.
–Jesse is an ISA certified arborist and a Senior Neighborhood Trees Specialist with Friends of Trees.