Butternuts and walnuts are deciduous trees with scaly, furrowed bark. Pith is chambered and colored. Buds have few scales. Flowers are monoecious. Male flowers are borne in long catkins. Female flowers are rounded and have conspicuous, red-fringed stigmas. Fruit is a large drupe with a two- to four-celled nut.
Juglans cinerea–Butternut
Juglans nigra–Eastern Black Walnut.
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| Butternut |
Butternut–Juglans cinerea
The butternut is known as white walnut in the south and is a smaller tree than the black walnut, although it may reach a height of 70 feet with a diameter of 3 feet. The trunk is usually forked, or crooked, making it less desirable for saw timber. Butternut is normally found in a more mesic site than is black walnut, such as above the floodplain along a slope.
Winter buds have few scales. Terminal buds are large, 1/2—1 inch (13—25 mm) long. The bark is lighter than that of the black walnut: light gray on branches and the trunks of small trees, becoming darker on larger trees. Mature bark is deeply fissured. This tree may also be distinguished from black walnut by the velvet collars just above the leaf scars left by the previous year's leaves. Pith is dark brown in color, chambered after the first season, and a good identification characteristic.
The odd-pinnately compound leaves are 10—20 inches (25—51 cm) long. Each leaf has 11—19 sharp-pointed, oblong, and finely toothed leaflets that are 2—3 inches (5—7 1/2 cm) long. The black walnut has more leaflets than the butternut on average.
The flowers are of two kinds and on the same tree. The male flower is borne in long, yellowish-green, drooping catkins. Female flowers are recognized by the rather conspicuous, red-fringed stigmas. The fruit is a nut enclosed in an oblong, somewhat pointed, yellowish-green husk about 2 inches (5 cm) long which is covered with short, rusty, clammy, sticky hairs. The butternut has a rough, grooved shell and an oily, edible kernel.
The wood is light, soft, not strong, coarse-grained, and light brown. The wood takes a good polish. It is used for interior finish of houses and for furniture. A yellow or orange dye can be made from the husks of the nuts.
Eastern Black Walnut–Juglans nigra
This valuable forest tree occurs on rich bottom lands and moist, fertile hillsides throughout the state. In the forest, the black walnut frequently attains heights of 100 feet with a straight stem, clear of branches halfway up the tree. Growing in open areas, the stem is short and the crown is broad and spreading.
The leaves are alternate and odd-pinnately compound. Leaves are 1—2 feet (30 1/2—61 cm) long, and have 15—23 leaflets. Foliage is a yellowish-green color. The leaflets are about 3 inches (7 1/2 cm) long, lanceolate in outline, and irregularly toothed along the margin. Leaf scars lack a hairy, felt-like margin on the upper edge of the leaf scar.
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| Eastern Black Walnut | ||
Buds have few scales. Terminal buds are smaller than the butternut and about 1/3 inch (8 mm) long. Lateral buds are smaller than the terminal buds. Pith in the twigs is buff-colored and chambered after the first season. The bark is thick, dark brown in color, and divided by rather deep fissures into rounded ridges.
Black walnut and butternut are allelopathic and produce a compound called juglone. This compound will injure some other plants. Many plants in the rose family and heath family are very sensitive and will be injured or killed if planted beneath the drip line of a black walnut tree. Other plants such as bluegrass grow very well beneath the crowns of black walnut or butternut trees.
Flowers are monoecious. Male flowers are borne in long catkins. Female flowers are rounded and have conspicuous, red-fringed stigmas. The fruit is a large drupe with a two- to four-celled nut. The fruit is borne singly or in pairs and enclosed in a solid green husk which does not split open even after the nut is ripe. The nut itself is black with a very hard, thick, finely ridged shell, enclosing a rich, oily kernel which is edible and highly nutritious. This tree produces the black walnut nuts of commerce, but the fruit is considered a liability in an urban site. Walnut trees are easily propagated from the nuts. Seedlings grow rapidly on good soils.
The heartwood is of superior quality and value. Black walnut is the most valuable timber species in Ohio. It is heavy, hard, strong, and of a rich, chocolate brown color. Freedom from warping and checking, acceptance of a high polish, and durability make it highly prized for a great variety of uses, including furniture and cabinet work, gun stocks, and airplane propellers. Small trees are mostly sapwood, which is light-colored and not durable. Urban trees have no timber value since they may contain metal, such as nails, in the wood.