Nanny called the black walnut tree El Capitan. “Let them dry on window sills,” she said. “The sun will do half the work for you.” And once the sun had done its work, with an old hammer in her right hand and a cast iron clothes iron squeezed between her aproned knees, Nanny smashed open the walnuts on the flat side of the iron and let the pulverized bits of shell fall to the floor. She repeated the violence over and over again until she was surrounded by a field of brittle carnage. The small nuts, hardly worth the effort with their oily bitter taste, would then sit on window sills to dry again. Once dry and chopped, she baked black walnut pound cake from scratch, scooping flour and sugar from dented metal tins in the cupboard.

***

In seventh grade, while your mother tried to recreate this cake with a Betty Crocker mix and some stale store-bought nuts, she told you the story of your great-grandmother, Nanny. A woman with hands so thick and skin so hard she was as impenetrable as her iron, her hammer, and her giant El Capitan walnut tree. Your mother’s loaf came out of the oven flavorless and dry, but you ate it anyway, imagining the earthy sweet flavor of Nanny’s cake. You choked down the bites with a large glass of milk.

***

In middle school science class, you learned the black walnut tree is a killer. An allelopathic tree. A tree that poisons other plants. Its roots contain a toxin, juglone, that can kill sensitive plants: tomatoes, azaleas, peppers, apples, cabbage, lilacs, and chrysanthemums. You knew girls whose tongues dripped juglone in middle school. The ones whose toxic roots reached far and wide. Who told you your ass was too big and your boobs were too small. They made fun of your Kmart clothes so you snuck your older brother’s rugby shirts out of his closet and pretended they were yours. They told you your bangs were thin and flat so you bought more hairspray.

***

While on a trip many years later, your mother discovered a black walnut tree and collected a giant bag of unshelled nuts, packed them into her suitcase, and flew them home. In your linoleum-floored kitchen, she attempted to crack them open just as Nanny had done, pulling an old iron used as a bookend off a shelf and fishing a hammer out from underneath the sink. The shells, still fresh and damp, not ready for cracking, smashed into a mealy green paste.

***

In science class you also learned there are some plants that tolerate and even thrive on juglone: birch, maple, ferns, carrots, and beans. Even certain tulips. You want to be one of those tolerant plants—less sensitive, thicker skin, hardier. To grow in spite of poison. You want to hold a hammer in your hand and squeeze an old iron between your knees. You want to hear the satisfying crack of shells and inhale the earthy smell of black walnuts drying on a sunlit window sill.