The black walnut is a Chicago-area native tree that provides excellent shade for large properties. It needs to be sited with care, since the tree produces a chemical that is toxic to some other plants. The fruit is a rounded, yellow-green husk containing a nut that is a food source for squirrels. The black walnut also attracts the banded hairstreak butterfly, serving as a caterpillar host.
This species is native to the Chicago region according to Swink and Wilhelm’s Plants of the Chicago Region, with updates made according to current research.
- Family (English) Walnut
- Family (botanic) Juglandaceae
- Planting site City parkway, Residential and parks, Wide median
- Tree or plant type Tree
- Foliage Deciduous (seasonally loses leaves)
- Native locale Chicago area, Illinois, North America
- Size range Large tree (more than 40 feet)
- Mature height 50-75 feet
- Mature width 30-50 feet
- Light exposure Full sun (6 hrs direct light daily)
- Hardiness zones Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9
- Soil preference Alkaline soil, Moist, well-drained soil
- Tolerances Alkaline soil, Clay soil, Occasional drought, Road salt
- Season of interest early fall
- Flower color and fragrance Inconspicuous
- Shape or form Round
- Growth rate Moderate
- Transplants well Yes
- Planting considerations May be difficult to find in nurseries, Messy fruit/plant parts
- Wildlife Cavity-nesting birds, Game mammals, Songbirds
- Has cultivars Yes