Black walnut (Juglans nigra) — Plotwright

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Black walnut

Habit (mature) · Plant Image Library (Boston, USA) / Wikimedia Commons · CC BY-SA 2.0

Limited coverage

Black walnut

Juglans nigra

A large deciduous timber and nut tree of eastern North America, growing 75-100 feet tall with an oval to rounded crown and dark, deeply furrowed diamond-patterned bark. Pinnately compound leaves carry 13-23 strongly aromatic leaflets, and yellowish-green flowers in May-June ripen into hard-shelled edible nuts inside green husks. Its roots and tissues release juglone, a compound that suppresses azaleas, rhododendrons, blueberries, peonies, and tomato-family crops planted nearby.

Native: 39 US states + 1 CA province

Review: Source-backed

Climate fit: broad (83/100)

Structure

Focal point

Light

Full sun

Water

Moderate water

Mature size

900-1200" tall · 480" apart

Hardy in zones

4a-9b

very cold to frosty winters

Summer heat range

Cool-Hot

cool to hot summers Interim Plotwright tier until the plant AHS range is authored.

Native in Illinois

Yes

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A documented larval host for the Luna moth and 2 other species — caterpillars feed on its foliage before becoming the next generation.

Wildlife relationships

Cold hardiness

Now

Zone 6b

USDA

Chicago, IL · 1991-2020 average annual coldest day

Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer

Well-suited

2050

Zone 7b

Plotwright

Your zone + climate-model shift · SSP3-7.0 (regional rivalry)

Well-suited

In plain terms: cold winters — coldest nights typically around -3°F.

✓

Well-suited today and still thriving in 2050.

Heat tolerance

°C

°F

Loading current AHS heat-zone and plant heat-fit data at your coordinates…

Where this plant fits

Suitable across 41 ecoregions — 40 climate-resilient through 2070 · 1 suited today. Best matches first.

Appalachian mixed mesophytic forests

Appalachian-Blue Ridge forests

Arizona Mountains forests

Atlantic coastal pine barrens

Blue Mountains forests

Canadian Aspen forests and parklands

Central Pacific Northwest coastal forests

Central Tallgrass prairie

Central-Southern Cascades Forests

Chilean Matorral

Sources & citations

Cite this page

For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.

Plotwright. (2026, May 17). Black walnut (Juglans nigra). Retrieved 2026, June 5, from https://plotwright.garden/plants/black-walnut

Sources for every fact

Every fact on this page traces to a source. 18 fields cited — 18 source-backed.

Missouri Botanical Garden PlantFinder

Botanical research database

Backs 17 fields

Identity

Summary

Plant type

Light

Moisture

Hardiness

Heat zone

Size

Spacing

Habit

Design roles

Seasonal interest

Growth stages

Lifecycle

Regional guidance

Success tips

Designer notes

Wikimedia Commons

Photo · CC BY-SA 2.0

Backs 1 field

Image

Lady Bird Johnson Wildflower Center Native Plant Database

Botanical research database

Community photos

The photos above are our reviewed reference set, curated for accuracy.

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