Walnut is
the name of a type of tree valued for its nuts and wood. Several species
of walnut trees grow in the United States. Two of these are native to
the East--the black walnut and the butternut, also called the white
walnut. Another species, the English walnut or Persian walnut, was
brought to the United States from southern Europe. It is grown
commercially in California and Oregon. Black and English walnut trees
provide high-quality wood for furniture.
English
walnut trees produce walnuts that have the greatest commercial value.
They are large, spreading trees that grow up to 100 feet (30 meters)
tall. They have gray bark, large leaflets, and soft wood. They have been
grown commercially in Europe since ancient times.
The English
walnut tree bears clusters of small flowers called catkins. The flowers
may be cross-pollinated or self-pollinated. After flowering, the tree
produces walnuts. The nuts have thin shells and taste mild and sweet.
They contain mostly fats and some proteins.
Growers
typically plant English walnut trees at least 60 feet (18 meters) apart.
But several varieties may be planted closer together. English walnut
trees thrive in deep, well-drained soil. After the nuts ripen, they are
shaken from the trees, hulled, and dried. The nuts are taken to packing
houses and are sorted and sized. They may be packaged either in the
shell or shelled. The poorer grades of nuts are used to make walnut oil.
Growers once
left walnut shells that fell to the ground as waste. Today, the shells
are collected and used in glues and plastics. They are also used to make
solutions for cleaning and polishing metal surfaces.
The United
States leads the world in the production of walnuts. Other major
walnut-growing countries include China, Greece, and Turkey. The U.S.
walnut industry is centered in the area around Stockton, Calif. In
addition, several hardy varieties of English walnut trees are grown in
the Midwest and the East. But growers usually do not plant large
orchards of these varieties. English walnut trees do not grow well in
the South.
Black walnut
trees grow in forests from Massachusetts to Florida and west to Texas.
They are hardy trees that are grown mainly for their lumber. The nuts
also are harvested and sold. They have a distinctive and rich flavor,
but their shell is hard and thick. They are usually shelled before they
are sold. Growers have also developed a few thin-shelled varieties of
these nuts.
Black walnut
wood is dark purplish-brown, with a fine grain and luster. It is
valuable for interior finishing, furniture, and gunstocks. This wood is
becoming rare.
Scientific
Classification. Walnuts belong to the walnut family, Juglandaceae. The
scientific name for the English walnut is Juglans regia. The black
walnut is J. nigra, and the butternut is J. cinerea.
Contributor:
Richard A. Jaynes, Ph.D., Horticulturalist and Consultant, Broken Arrow
Nursery.
