PLANT OF THE WEEK
Dr. T. Ombrello - UCC Biology Department
Black Walnut, American Walnut
Scientific name: Juglans nigra
of scientific name:
- From the 2
Latin words “Jovis” meaning Jupiter and “glans” meaning nut.
The word is used most likely in
reference to the ancient common name for walnut fruit:
nut of Jupiter.
Latin for dark or black.
A 20 year old Black Walnut tree.
Found from Massachusetts
to Georgia and west to the Great Plains, the Black Walnut is an imposing tree
that has a long history of use by people. Preferring
the deep, rich, moist, but well drained soils of floodplains and stream
terraces, the tree rarely dominates a woodland, but is often located in
association with other hardwoods such as ashes, elms, maples, and sycamores.
utilized the tree for its nuts (eaten raw or pounded into a “butter”) and
tapped the trunk for sap to make syrup in the same way sugar maples were.
The Black Walnut fruit
ripens in October and has a yellow-green husk that encloses a black, round nut 1
to 2 inches in diameter. The nut
contains a fleshy, oily, but quite edible kernel.
Unlike its European relative the “English” or more appropriately, the
“Persian” Walnut, the Black Walnut’s kernel is quite difficult to extract
from the fruit. The immature husk
yields an indelible yellow dye that becomes an indelible black dye as the husk
begins to deteriorate. The dye
stains everything, including fingers.
American Indians and the pioneers used it to dye their homespun cloth.
The husk is quite firmly attached to the nut inside.
Very difficult to crack, suggestions for breaking the nut range from
running one’s car over it to attacking it with a hammer.
Why would one want to
bother? The nut is nutritious, stores well, and becomes available when
many other foods are scarce in the fall. So,
Native Americans and early colonists (beginning with Jamestown in 1609) searched
for it. Since the kernel’s distinctive flavor and texture are not
lost in cooking, it is still used today (50 million pounds each year
commercially and untold amounts for home use) in cakes, candies, and that
traditional American favorite, Black Walnut ice cream.
New varieties of Black Walnut have been developed.
They bear fruit earlier in their lives (2 to 3 years after planting) with
easier to crack nuts yielding half or even whole kernels instead of just small
Other interesting uses
for the fruits would include grinding up the nutshells for cleaning abrasives
and gas mask filters. One use,
found by accident by the author, would be of interest to fishermen.
Husks and nuts allowed to sit in a bucket of water for several hours will
produce a dark brown/black liquid, which if poured over soil will in minutes
drive every earthworm in the area up to the surface for easy picking.
While their nuts are of
interest and of economic importance, the wood is by far the most valued part of
this species. The early colonial
settlers in America soon discovered the wood to be hard, yet soft enough to work
easily. It is coarse grained,
finishes well, absorbs shock, only shrinks slightly when dried, and resists
decay. The outer sapwood of the
trunk is white and not highly valued, but the inner heartwood is a rich dark
chocolate brown of just about unsurpassed quality.
It was valued then, and even today it is undoubtedly the most sought
after native American wood. Used
primarily for furniture, antique pieces may be of solid walnut.
Today, because of its rarity and expense, Black Walnut is cut into thin
(1/32 or 1/64 inch) sheets – veneers to be glued onto inferior wood for most walnut
furniture. As in the past, Black
Walnut is the wood to use for
gunstocks. Black Walnut paneling is
available but is quite expensive. Until
it was replaced by synthetics, the wood was used for airplane propellers.
the demand is so great, they are rare in nature, and their growing time is so
long (a minimum of 60 years to get a reasonably large trunk), we cut many more
Black Walnuts than are started. Buyers
search out smaller and smaller trees as their value rises.
Prices are ridiculous. A
well grown, straight trunked, 200 year old tree can sell for tens of thousands
of dollars. But, such a tree could yield enough black walnut veneer to
cover nearly 3 acres.
Black Walnut thieves are
becoming common. Usually posing as
tree surgeons, they appear when homeowners are away and make off with the trees
in a matter of hours. Eight trees worth over $50,000 were cut from a property in
Michigan, and at least several Black Walnut thefts are reported annually in New
Jersey. While not a danger of
extinction, Black Walnut trees are becoming less common in the landscape.
Defenseless against a
person with a chainsaw, Black Walnut trees do, however, have the capability of
defending against plant competitors. Black Walnut roots secrete a hormone, juglone, that will
retard or kill such plants as alfalfa, tomato, potato, blackberry, blueberry,
and rhododendron among others. This
chemical inhibition of surrounding vegetation is termed allelopathy.
While some plants are hurt, other surrounding plants are promoted.
Beets, beans, corn, bluegrass, raspberry, grape, and even poison ivy are
helped, or at least unaffected by the juglone.
An all-American tree that is exploited but certainly not unappreciated by those who recognize its beauty, the Black Walnut’s status and value are likely to continue to rise.