Black Walnut Trees

Though in full leaf for less than three weeks, our black walnut trees already have small fruits growing at the tip of their stems. Over the next few months, these walnuts, encased in a leathery, green skin and pungent black pulp, will grow to a diameter of 2 inches and, by mid August, will begin falling to the ground.

Favoring alkaline soils, black walnuts are common across the Midwest and Northeast, concentrating in regions with limestone bedrock (such as the Missouri Ozarks and the Ohio River Valley). Large trees, often reaching 100 feet in height, they are resistant to natural pathogens and may live 250 years; unlike their close relatives, hickories and butternuts, they prefer moist lowlands.

Heavily used by eastern gray squirrels for food and shelter, the black walnut has long been exploited for both its fruit and its hard, fine-grained wood, used primarily for furniture construction. We naturalists admire its massive frame, its seasonal bounty, its distinctive fragrance and its appeal to varied wildlife species, from tent caterpillars to great horned owls.