Black Walnut

• Long compound leaves with 15–23 narrow leaflets
• Round green husked nuts in late summer
• Dark, deeply furrowed, diamond-patterned bark
• Stout twigs with chambered tan pith

Native range

Native to the eastern and central United States, including the creek bottoms and rich uplands of eastern Kansas. Valued enough as timber that mature trees are occasionally stolen.

Soil

Wants deep, well-drained, fertile soil near neutral pH. Struggles noticeably on thin, dry, or compacted ground.

Sunlight

Full sun

Drought & heat

Moderate drought tolerance, high heat tolerance.

Excellent in a big east-Kansas yard, away from gardens, patios, and parking. Keep vegetable beds well outside the root zone.

Deep taproot, and chemically active: the roots release juglone, which kills tomatoes, peppers, potatoes, eggplant, and many ornamentals growing within the root zone. That zone extends well past the drip line, so keep vegetable beds outside it entirely.

Good. Strong, dense wood and sound branch structure; storm failure is uncommon in a healthy tree.

Overall storm resistance: Good. Assessing damage after a storm

• Walnut caterpillar

  Manageable

  Colonies of dark, hairy caterpillars strip branches bare in mid to late summer, clustering on the trunk to molt. Established trees recover; young ones benefit from intervention.

• Thousand cankers disease

  Serious

  A fungus carried by the walnut twig beetle, producing countless small cankers under the bark and progressive crown dieback. Not yet widespread in Kansas, and worth reporting to the state forest service if suspected.

• Anthracnose

  Cosmetic

  Dark leaf spotting and early defoliation in wet years. Walnut sheds its leaves early regardless; this simply accelerates it.

Seeing something not listed here? Work from the symptom instead

Best windowLate summer or midwinter — avoid late winter and early spring, when it bleeds heavily

Prune in August or in the depth of winter. Cut in February or March and the tree will run sap freely from every wound; it is not fatal, but it is messy and stresses the tree.

Use caution — not for structural reasons but for what falls. Nuts drop hard enough to dent a car and stain concrete and drives black, and juglone rules out a garden nearby.

• Advanced trunk decay above a target
• Thousand cankers disease confirmed — report it, since it is not yet widespread in Kansas

Removal is a judgment call about risk, not a formula. A tree with one of these conditions over open lawn is a very different situation from the same tree over a driveway — and that judgment needs someone on site.