Black Walnut
 

Mature Size, Growth, Longevity

Average mature size of 50-70' tall and wide. Fast growth rate, 2-3' per year when young and in favorable soils. Long lived, matures at about 150 years, may live to 250 years.

Native Range

Kentucky Native — Massachusetts to Florida, and west to Minnesota and Texas.

Flower and Fruit Details

Flowers are yellow, late May - early June, monoecious: male flowers clustered in short, pencil-like drooping catkins. Fruits are a green, smooth, 2" diameter husk, containing a corrugated nut. Husks are very odiferous and can turn your hands green and smelly if you pick them up, they eventually turn black and rot on the ground.

Leaf and Bark Features

Golden yellow fall color, but leaves drop early. Dark brown to grayish-black, divided by deep, narrow furrows into thin ridges, forming a roughly diamond-shaped pattern.

Culture and Care

Prefers deep, rich, moist soil but can tolerate drier, clay soils. Zones 4-9. Few insect or disease problems on healthy trees. Most notable is a thousand cankers disease, caused by a canker producing fungus, Geosmithia morbida, vectored by the walnut twig beetle, Pityophthorus juglandis.

Strengths, Weaknesses, Other Facts

Roots produce juglone, which is harmful to many other plants growing in its root zone. Wood is highly prized for carpentry uses. Young stems have a chambered pith in the center, a good identification feature.

Taxa and Plants of this Species at BCA