What hardiness zones is Juglans nigra suitable for?

Juglans nigra is suitable for USDA hardiness zones 4, 5, 6, 7, 8, 9.

What are the sun requirements for Juglans nigra?

Juglans nigra requires Full Sun.

How much water does Juglans nigra need?

Juglans nigra has Medium water needs.

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Broadleaf Deciduous Trees

Juglans nigra

black walnut

JuglandaceaeEastern and central North America

At a Glance

TypeTree

HabitUpright

FoliageDeciduous

Height50-75 feet (15-23 m)

Width50-75 feet (15-23 m)

Maturity20 years

Growing Zones

USDA Hardiness Zones

4 - 9

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

These zones indicate the coldest temperatures this plant can typically survive.

Frost Tolerancehardy

Key Features

Attracts Butterflies

Deer Resistant

Drought Tolerant

Native to North America

Maintenancemoderate

Overview

Juglans nigra is a large deciduous tree reaching 50-75 feet (15-23 m) tall with a spread of 50-75 feet (15-23 m) at maturity, developing a rounded to broadly oval crown. The trunk grows straight with deeply furrowed, dark brown to black bark arranged in diamond-shaped ridges. Alternate, pinnately compound leaves measure 12-24 inches (30-61 cm) long with 15-23 lance-shaped, finely serrated leaflets, each 2-5 inches (5-13 cm) long. Foliage emerges yellow-green in spring, matures to dark green, and turns yellow in autumn before dropping earlier than most deciduous trees, typically by mid-October. Inconspicuous green catkins appear in April to May concurrent with leaf emergence. Female flowers on the same tree develop into round, 1.5-2.5 inch (4-6 cm) diameter fruits enclosed in thick green husks that stain skin and surfaces dark brown when handled. The edible nuts inside have a rich, distinctive flavor but thick, hard shells requiring mechanical cracking. Roots produce juglone, a chemical compound toxic to many plant species including tomatoes, peppers, azaleas, and blueberries, with concentrations highest within the dripline. Growth rate is moderate to fast at 12-24 inches (30-61 cm) per year in favorable conditions. Trees are long-lived, commonly reaching 150-250 years. Wood is highly valued for furniture and veneer.

Native Range

Native to eastern North America from southern Ontario to central Texas, east to the Atlantic coast from Massachusetts to northern Florida. Occurs naturally in rich bottomlands, stream banks, and well-drained slopes at elevations from sea level to 4,500 feet (1,370 m). Most common in deep, fertile soils of the Ohio and central Mississippi river valleys.

Suggested Uses

Commonly planted as a shade tree or specimen on properties with space for its mature spread of 50-75 feet (15-23 m). Used in nut orchards, agroforestry plantings, and timber production. Not suitable for small gardens or mixed plantings due to juglone toxicity to many companion species.

How to Identify

Identified by pinnately compound leaves with 15-23 finely serrated leaflets, the terminal leaflet often smaller or absent. Bark is dark brown to black with deep, diamond-shaped furrows. Round green fruit husks, 1.5-2.5 inches (4-6 cm) in diameter, do not split open at maturity, unlike Juglans regia. Pith of twigs is chambered (light brown), visible when a twig is cut lengthwise.

Appearance

Size & Dimensions

Height50' - 75'

Width/Spread50' - 75'

Reaches mature size in approximately 20 years

Colors

Flower Colors

green

Foliage Colors

green

Fall Foliage Colors

yellow

Bloom Information

Bloom Period

~2 weeks

Spring

Inconspicuous male catkins, 2-5 inches (5-13 cm) long, appear in April to May as leaves emerge. Female flowers are small, greenish, and borne in short terminal clusters on the same tree. Wind-pollinated; bloom period lasts approximately 1-2 weeks. Fruit matures in September to October.

Detailed Descriptions

Flower Description

Green (inconspicuous catkins)

Foliage Description

Dark green, emerging yellow-green in spring

Growing Conditions

Sun Requirements

Full Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

loamsiltclay

Drainage

well drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

10-15 years to nut production

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Water deeply once per week during the first two growing seasons to establish the taproot. Established trees tolerate drought but produce more nuts with consistent moisture during fruit development in July through September. Plant in full sun with at least 6 hours of direct light for best nut production; trees in partial shade grow taller with fewer nuts. Apply 2-3 inches (5-8 cm) of organic mulch over the root zone, keeping mulch 6 inches (15 cm) from the trunk. Juglone toxicity extends 50-80 feet (15-24 m) from the trunk in mature trees; avoid planting susceptible species within this zone. Webworm, anthracnose, and thousand cankers disease (caused by the walnut twig beetle and Geosmithia morbida) are potential concerns, particularly in western regions.

Pruning

Prune in late summer to early fall (August through October) to minimize bleeding of sap, which occurs heavily with winter or spring pruning. Remove dead, damaged, or crossing branches. Establish a central leader in young trees by removing competing leaders in the first 5-8 years. Avoid removing more than 25% of the canopy in a single year.

Pruning Schedule

summerfall

Maintenance Level

moderate

⚠️ Toxicity Warning

Toxic to pets and humans