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Common Name:

Black Walnut

Scientific Name:

Juglans nigra

Family Name:



Black Walnut is a large native forest tree from Eastern North America, including East Texas. Trees tend to develop a stout trunk with a rounded crown when open grown, but are more frequently encountered as trees in competition with long boles and a narrower upright oval crown. The wood is highly valued for cabinetry and veneers. The fruit is an edible nut, which is eaten by both humans and wildlife.

Plant Habit or Use:

Medium tree, large tree



Flower Color:

Yellow-green, males in catkins, females inconspicuous, not ornamental

Blooming Period:


Fruit Characteristics:

Stronly furrowed woody nut encased in a green to to black-brown leathery husk, meat of nut edible


50 ft to 60 ft (120 ft)


35 ft to 50 ft

Earth–Kind® Index:

  • Heat Tolerance: High Heat Tolerance
  • Water Requirements: Low Water Use
  • Soil Requirements: Low Soil Requirements
  • Pest Tolerance: Medium Pest Resistance
  • Fertility Requirements: Low Fertility Requirements
Explanation of the Earth–Kind® Index breakdown

Firewise Index

Explanation of the Firewise Index numerical value

USDA Hardiness Zones:

4, 5, 6, 7, 8, 9

Regions that intersect these hardiness zones:
Region A - Panhandle and High Plains Region B - North and Central Texas Region C - Northeast and East Texas Region D - West Texas Region E - Upper Rio Grande Region F - Hill Country and Central Coast Region G - Southeast Texas Region H - Rio Grande Valley
Click image for enlarged map of USDA Hardiness Zones

Additional Comments:

Walnuts are allelopathic to some plants. A strong taproot hinders transplanting. Nuts are a maintenance problem and trees often defoliate prematurely in late summer or early fall in response to drought or disease. Husks stain whatever they contact.
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A Special Note about Cool Season Annuals

Cool season annuals typically are planted in the fall or early winter and flower in early spring under moderate temperatures. This group of plant materials includes: pansies, snapdragons, violas, dianthus, flowering cabbage/kale, etc. Because cool season annuals flower in the spring when conditions are mild, most have limited heat tolerance.

As a result cool season annuals do not receive a high Earth–Kind® index despite their outstanding landscape qualities.