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kudzu (Pueraria lobata)

ODA rating: A and T
Kudzu risk assessment
Noxious weed listing process

Oregon kudzu distribution
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Images courtesy of Tom Forney, Oregon Department of Agriculture

If images are downloaded and used from the ODA web site please be sure to credit the photographer.
This high climbing vine often completely covers trees, shrubs and man-made structure forming “kudzu sculptures”. The leaves are alternate, six to eight inches long, have fuzzy leaflets three to four inches long, oval, lobed or nearly heart shaped. Flowers are large hanging clusters of pea-like, purple to red color, with a grape-like smell and appearing in midsummer. Fruit are dark brown flattened pods in clusters, very hairy and ripens in the fall. Stems are velvety with hairs turning brown. Trunk or vines may reach up to four inches in diameter. Older stems and vines turn brown and smooth and eventually form a fine scaly bark. Vines may extend thirty to one hundred feet in length with stems one half to four inches in diameter. As many as thirty vines may grow from a single root crown. Roots are fleshy massive taproot seven inches or more in diameter, six feet or more in length and weighing as much as four hundred pounds.
Kudzu kills or degrades native and desirable plants by smothering them under a solid blanket of leaves, by girdling woody stems and tree trunks, and by the sheer force of its weight breaking branches or uprooting entire trees and shrubs. Trees covered by kudzu become damaged by its weight during ice events or die from insufficient light. Once established kudzu grows at a rapid rate extending as much as 60 feet per season at a rate of about one foot per day.  Kudzu grows well under a wide range of conditions and soil types. It favors habitats such as forest edges, abandoned fields, roadsides, and disturbed areas where sunlight is abundant. Kudzu grows best where winters are mild, summer temperature are above eighty degrees and annual rainfall is fourty inches or more.
Kudzu was introduced to the United States in 1876 at the Centennial Exposition in Philadelphia, Pennsylvania. At a celebration of 100th birthday of the U.S. the Japanese government constructed a beautiful garden filled with plants from their country. The large leaves and sweet-smelling blooms of kudzu captured the imagination of American gardeners who used the plant for ornamental purposes. During the Great Depression of the 1930s, the Soil Conservation Service promoted kudzu for erosion control later declaring it a noxious weed.  Kudzu is also noted to have medicinal values and culinary uses.
Distribution in Oregon
Four kudzu sites are known in the Pacific Northwest, three Oregon sites are undergoing intensive treatment. Several sites have been reported and additional kudzu finds are expected. Prior to 2000 Kudzu was not found west of Texas. Between 1935 and the mid 1950’s Kudzu was planted in the southeastern U.S. for forage and erosion control. Kudzu has since become a major noxious weed impacting millions of acres.
For a collection of spatial information on the distribution of this plant in Oregon go to Oregon WeedMapper.

Biological controls
No approved biocontrol agent is available. This weed is being managed for eradication.
Printable Kudzu trifold brochure (pdf)