Kudzu
(Pueraria lobata (Willd.) Ohwi)
In
Georgia, the legend says
That you must close your windows
At night to keep it out of the house.
The glass is tinged with green, even so...
From the poem, "Kudzu,"
by James Dickey (21)
DESCRIPTION:
Kudzu is a trailing and climbing vine in the legume family. A native
of China and Japan,
the kudzu plant is a coarse-growing perennial with trifoliate leaves
that have coarsely lobed leaflets. (22) It produces large,
wisteria-like, purple flowers on long racemes, and beans in flat, papery
pods covered with a tawny down. Kudzu plants produce long lateral runners
that generate roots at intervals. Being a member of the bean family
(Fabaceae), bacteria in the roots fix atmospheric nitrogen, thus
increasing soil fertility wherever kudzu grows. Kudzu vines can grow one foot in a
single day. The tuberous roots of up to 17.8 centimeters
in diameter
can reach a depth of 18 feet and weigh 200-300 pounds. (23) Forest edges or
disturbed areas such as abandoned fields and roadsides are preferred
habitats.
INTRODUCTION
HISTORY AND DISTRIBUTION: Kudzu was introduced to the United States in 1876 at the Centennial Exposition in Philadelphia, PA
and into the South at the New Orleans Exposition during 1884-1886.
The large leaves and sweet-smelling blooms of kudzu captured the imagination
of American gardeners, who used the vine for ornamental and shade purposes.
(21) Nursery operators discovered that the vine was edible
by animals and promoted its use as a forage crop; however, kudzu is
difficult to harvest and bale for hay. Kudzu was introduced originally
for erosion control in the early 20th century. During the
Great Depression of the 1930s, the Soil Conservation Service promoted
kudzu for erosion control in the southeastern United States.
Hundreds of young men were given work planting thousands of acres of
kudzu through the Civilian Conservation Corps. By 1934, CCC laborers
had planted over 85 million kudzu seedlings. (23) Farmers were
paid as much as eight dollars an acre as incentive to plant fields of
the vine in the 1940s; however, kudzu was declared a common weed of
the south by the USDA in 1970. (21)
Kudzu
is found all over the southeastern United States,
covering up to an estimated 7 million acres. It is found north to Pennsylvania and Connecticut, and west to Texas and Oklahoma.
Kudzu was discovered for the first time west of Texas in August of 2000, when an infestation
along a roadside in Clackamas County was reported to the Oregon Department
of Agriculture. (24)
IMPACTS
ON ECOSYSTEM: Where it grows, kudzu can out-compete and eliminate native
plants and upset the natural diversity of plant and animal communities.
(22) Kudzu grows rapidly, up to 60 feet per year in ideal conditions,
choking out competing vegetation in sunny areas. Climbing vines may
completely cover and shade out trees, and may cover and damage buildings,
overhead wires, and other structures. The weed overwhelms native plants,
literally smothering other species, and is a threat to riparian areas
and watershed health. (21) This massive covering often removes
native vegetation that provides food and habitat for native animals
within an ecosystem. The result is a large-scale alteration of biotic
communities. (23) The vine’s huge root systems develop deep
into the ground, can affect soil water levels, and ultimately alter
the hydrology of an area.
CONTROL
EFFORTS: Kudzu,
with a deep and extensive root system, is difficult to control once
it has become established in an area. Native insect pests from Asia
were not brought to the US
with the plant. Persistent, mechanical eradication efforts towards
eliminating all roots are the best method of control. Grazing or mowing
can work well on young, not-well-established patches. (22) Glyphosates
are recommended for long-term herbicide treatment, One researcher found
that one herbicide actually facilitated growth and that most others
are ineffective. (21)