Boone County Arboretum
9190 Camp Ernst Road
Union, Kentucky 41091
Phone: (859) 384-4999
Fax: (859) 384-6888
arboretum@boonecountyky.org

Open Daily
Dawn - Dusk
Free Admission

Join Our Email List
Email:  

Contact Us

Information on invasive species

Emerald Ash Borer Information

Horticutural Links

Donate to the Boone County Arboretum

Boone County Arboretum

Promote Your Page Too

Employee Login

Cultural Details for Juglans nigra

Common Name:
Black Walnut

Growth Rate:
Fast, 2-3' per year on favorable soils when young

Average Mature Height:
50-70'

Average Mature Width:
50-70'

Flower Details:
Yellow, late May - early June, monoecious: male flowers clustered in short, pencil-like drooping catkins

Fruit Details:
Corrugated nut in a green, smooth, 2" diameter husk which turns black and rots on ground.

Fall Color:
Golden yellow, drop early

Bark Details:
Dark brown to grayish-black, divided by deep, narrow furrows into thin ridges, forming a roughly diamond-shaped pattern

Disease / Insect Problems or Resistance:
Roots exude a substance toxic to many other plants, few insect or disease problems on healthy trees.

Native Habitat:
Massachusetts to Florida, and west to Minnesota and Texas

Other Features:
Wood is highly prized for carpentry uses. Branches have a chambered pit. Roots produce juglone which is harmful to many other plants growing in its root zone.

Culture and Care:
Prefers deep, rich, moist soil but can tolerate drier, clay soils zone 4-9

This plant was blooming:

Plantings of this cultivar at Boone County Arboretum:
980, 1233, 1234, 1235, 1236, 1237, 1238, 2214, 2285, 2532, 2538, 8614, 8615, 8616, 8630

    The information on this page may have come from one or more of the following sources:
  • Dirr, Michael. Manual of Woody Landscape Plants. Stipes Publishing. 1998.
  • Hightshoe, Gary L. Native Trees, Shrubs, and Vines for Urban and Rural America. John Wiley & Sons. 1988.
  • North Carolina Extension Plant Fact Sheets. www.ces.ncsu.edu
  • University of Connecticut Plant Database. www.hort.uconn.edu