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Hemp
Nature Bulletin No. 358-A November 15, 1969
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
HEMP
Primitive man probably made his first ropes and cords from animal
sinews. strips of hide, or the tough shoots of plants. Eventually, like
the American Indian, he learned to use plant fibers. Today, the
principal fiber plants are cotton, flax, hemp, manila hemp, sisal hemp
and jute.
Soft Hemp, a native of India and Persia, has been cultivated in China
since 2800 BC It reached western Europe about 500 AD and, for
centuries was one of the most important textile fibers. The first
colonists brought hemp to America. From it were woven the homespun
garments of our pioneers and the tops of their covered wagons.
Kentucky was once one of the leading hemp producing regions in the
world but, today, this has become a minor crop in the United States. It
is produced largely in Russia, Poland, Hungary, Italy, India and
China. Other fibers, natural or synthetic, have replaced it.
Soft hemp, or Marijuana, is the only true hemp. It is an annual plant
of the Mulberry Family, closely related to hops and nettles but having
the general appearance of the giant ragweed. A great deal of confusion
has arisen because the name "hemp" has been borrowed to label
several other fiber-yielding but unrelated plants, Manila hemp, or
Abaca, comes from the Philippines and greatly resembles its close
cousin, the banana plant. It is used for the better grades of rope
because its hard fibers are lighter, stronger and more resistant to water
than those of soft hemp. Sisal hemp and Henequen, two species related
to the century plant and native in Central America, are used for the
cheaper grades of rope, binder twine, wrapping twine, nets, etc. Sunn
hemp, native and widely grown in India, is used for coarse cloth and
burlap sacks, like jute. Bowstring hemp or sansevieria, is the "snake
plant" so common in our homes and hotel lobbies.
Hemp does best on rich river bottoms but has escaped to grow wild in
many places. When sown thickly for a fiber crop, it may be from 5 to
12 feet tall with stalks one-half inch or less in diameter. Planted in
hills, for seed, the stalks may be two inches thick and 20 feet tall. Each
leaf has from 5 to 11 slender toothed leaflets like the fingers on a
human hand. me inconspicuous flowers at the top of the stalk are of
two types, born on separated plants.
When the stalks are harvested for fiber, preferably when in full bloom
and by special machines, they are allowed to dry in shocks or in
stacks. men, in the United States and Russia, they are spread on the
ground to absorb rain and dew; in other countries they are usually
soaked in ponds or artificial tanks. This "retting" or rotting separates
the fibers -- from 4 to 8 feet long -- from the outer bark and the woody
inner shell, as well as from each other. me remaining processes, such
as rolling and "scutching" or combing, are similar to those used on
flax.
The "line" or long fibers are used to make rope, cordage, durable
twines, carpet yarns and thread, upholstery webbing and bolt webbing.
me short fibers, or "tow", are tarred to make oakum for caulking boats
and pipejoints. Oil from the seeds are used in soaps, paints and
varnishes. The seeds are fed to poultry, caged birds, and furnish winter
food for game birds. me flowers and upper leaves, dried and smoked,
contain a dangerous habit forming narcotic known as marijuana in
America, ganja in India, and Hashish in the Middle East.
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Update: June 2012
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