Black Walnut

Juglans nigra

tree

Black walnut (Juglans nigra) is a tall, stately native nut tree, 50 to 90 ft, with deeply furrowed dark bark, large ferny leaves, and round green fruits that ripen to richly flavored nuts in fall. Prized for its valuable dark timber and its bold, distinctive nuts, it also yields a strong brown dye from its husks and has a long folk tradition behind the husk and leaf. Its famous quirk is juglone - a compound in its roots, leaves, and husks that suppresses the growth of many plants beneath its canopy. It is grown for nuts and dye, and as a magnificent long-lived shade tree, sited well away from sensitive gardens.

✅ Plant alongside

Good neighbors that attract beneficial insects or deter pests

• Currant — Among the shrubs that tolerate juglone and can grow near a black walnut
• Black Raspberry — A juglone-tolerant bramble that can share the ground beneath the tree
• Clover — A nitrogen-fixing groundcover generally tolerant of juglone for the open ground nearby

❌ Keep away from

🛡️ Pest & disease prevention

Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide

• Thousand cankers disease →

  Spread by walnut twig beetle; keep trees vigorous, watch for dieback, and avoid moving walnut wood that can carry it

• Walnut caterpillar →

  Colonies strip leaves late in summer; prune out and destroy massed larvae

• Fall webworm →

  Prune out the silken nests at branch ends; damage is mostly cosmetic

🌾 Harvest & storage

Gather the nuts in fall as the green husks drop and begin to soften and blacken. Wear gloves - the husks stain hands, clothes, and concrete a deep, lasting brown (that stain is the traditional dye). Hull the nuts promptly, wash them, and cure the in-shell nuts a few weeks before cracking the hard shells for the rich kernels. Save the husks for dye. The leaves and husks are also the traditionally gathered parts; handle and use them knowingly given the staining juglone.

🥗 Nutrition & benefits

Black walnuts are richly flavored, oily, and nutritious, eaten out of hand and baked into cakes and candies once the tough shells are cracked. The husks give a strong brown dye and, with the leaves, are the traditionally gathered parts. Remember the juglone: it makes the tree a poor neighbor for tomatoes, apples, blueberries, and many garden plants, so place it thoughtfully.