Black Walnut (Juglans nigra)-Hort Answers - University of Illinois Extension
University of Illinois Extension

University of Illinois Extension

Hort Answers

Tree

Black Walnut
Juglans nigra

Black Walnut form
Black Walnut form
 
Features
Coarse compound leaves in summer; edible nuts in round husks in early autumn; fall color can be a good yellow. 
 
Culture
Full sun; moist, well drained soil; tolerates drought, alkaline pH. 
 
Cultivars
 
 
Mature Height
50-90 Feet
 
Size
Large
 
 
Mature Form
Oval to rounded with an open crown 
 
Native To:
United States (and Illinois) 
 
USDA Hardiness Zone
5 - 8 
 
Soil Conditions
Dry
Moist, Well-Drained
 
 
Tolerance
Alkaline Soil
Dry Sites
Wind
 
 
Exposure/Light Requirements
Full Sun
 
 
Uses
Shade
 
 
Foliage Color
Green
 
 
Fall Foliage Color
Yellow
 
 
Pests and Problems

Bacterial Disease

Environmental Damage

Fungal Disease

Insect Damage


Additional pests and problems that may affect this plant:

Walnut anthracnose often causes earlyleaf fall and so spoils fall color. Difficult to transplant due to deep taproot.
 
Additional Notes
The roots of black walnut produce a chemical, juglone, that can be toxic to certain plants.

 

 
Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic