How to kill kudzu

With nicknames like “the vine that ate the south,” kudzu is a force to be reckoned with. Introduced to the United States in 1876 at an exposition in Philadelphia as an ornamental plant, and later embraced by farmers in the Southeast for erosion control and animal grazing, kudzu has blanketed more than 7 million acres in North America (mostly in the Southeast), and is expanding at a rate of more than 120,000 acres a year.

What’s a gardener to do if faced with the threat of kudzu? A Decatur, Georgia teen known as the “Kudzu Kid” is getting quite a bit of attention for developing a way to kill the aggressive vine by injecting helium into its roots without harming the surrounding plants and wildlife (see the article in Atlanta Magazine). While this method is still being tested and debated, we’ve rounded up a few ideas from the front lines.

Faced and fought kudzu yourself? Frustrated gardeners will thank you if you share your strategies (short of hair-burning chemicals) in the comments section below.

Above: As if swallowing landscapes, altering ecosystems, and marching further northward weren’t enough, kudzu may also be contributing to ozone pollution, according to a recent report from The National Academy of Sciences. Image by Reophax via Flickr.

Above: Photograph by DM via Flickr. Don’t let the sweet-smelling purple kudzu blooms fool you. This vine is voracious; it can grow up to a foot per day.

No. 1: The best kudzu-fighting strategy is to keep it off your land in the first place. If it is creeping close by, this will take very active management. Build a barrier such as a tall fence that is buried at least 4 inches underground. Like pesky children, the vines will try to climb over fences.

No. 2: Roll back invading vines to keep them from invading. Don’t break or cut them as this will stimulate more growth. Others recommend building barriers of mulch, especially grass clippings, as a deterrent. Image by dmott9 via Flickr.

Above: The kudzu vine chokes forests, literally smothering trees and other plants, preventing them from getting sunlight. It is said to be herbicide resistant, so regardless of the negative health and environmental impact, herbicides should be crossed off the list. Photograph by Ken Ratcliff via Flickr.

Kudzu is creeping into New York and Pennsylvania, and has been found as far north as coastal Canada.

No. 3: Some like to fight fire with fire and turn kudzu’s smothering technique back on itself.

No. 4: Fully cover the kudzu with grass clippings or other mulch to rob it of light and oxygen. Plastic sheeting can also be used, creating heat to kill the plant.

Above: Kudzu on a bridge. Photograph by Suzie Tremmel via Flickr.

No. 5: Resort to the farmer’s method of keeping kudzu in check: overgrazing by animals. Several cities have used goats to fight kudzu infestations. They are voracious eaters and can easily navigate hilly terrain.

Relax. There are Vertical Climbing Plants to Embrace.

Finally, get more ideas on how to plant, grow, and care for various vines and climbers with our Vines & Climbers: A Field Guide.

Additionally, get more ideas on how to successfully control or eliminate kudzu with our Kudzu: A Field Guide.

How to Control Kudzu, the Vine That Ate the South

Last Updated: May 7, 2015 | by Mike McGroarty

Kudzu control? While travelling through the southern United States, it’s hard to miss seeing the lush green vines that sprawl throughout fields, drape luxuriously over trees and fences, and even over abandoned buildings. This is the aggressive kudzu vine and it has become a big problem.

The kudzu vine is not native to this country. A native of China and Japan, kudzu vine was introduced to the United States in 1876 during the Centennial Exposition that was held in Philadelphia to celebrate the nation’s 100th birthday.

To celebrate the centennial, the Japanese government created a beautiful garden exhibit filled with native Japanese plants, including kudzu. Unaware of its potential as an invasive plant, American gardeners soon began to grow kudzu for its attractive glossy foliage and heavily-scented blossoms similar to wisteria. Now, years later many people are looking for a way to control Kudzu.

Unfortunately, the spread of the invasive kudzu vine wasn’t limited to a few flower gardens. In the 1920s, owners of a plant nursery in Chipley Florida noticed that their goats and cows enjoyed eating kudzu, often passing up other tasty plants in favor of kudzu. Seeing this as a money-making crop, kudzu vine was soon being marketed as livestock fodder and the vines were being sent across the country through the mail.


Get my FREE Ebook, “The Gardener’s Secret Handbook”, along with a bunch of other really cool stuff just for signing up for my Free Gardening Newsletter!
Plus, I promise to send you gardening tips you won’t find anywhere else!

If that wasn’t bad enough, kudzu vine was spread even further through government programs during the Great Depression of the 1930s.

The newly formed Soil Conservation Service saw kudzu as a miracle vine that could control erosion, and hundreds of young men were employed by the Civilian Conservation Corps to plant kudzu vine for erosion control. During the 1940s kudzu was spread even further as farmers were paid the princely sum of eight dollars per acre to plant fields of kudzu vine.

It wasn’t until 1953 that kudzu vine was recognized for the invasive pest weed it is, and the Department of Agriculture finally removed it from its list of acceptable cover crops. But by then the damage was done and kudzu continues to spread, reaching as far north as Pennsylvania, Illinois, Indiana and Missouri. There are now two million acres of kudzu vine growing across the South.

Wanted! People who would like to work at home
making and selling rooted cuttings.

Kudzu vine is a semi-woody perennial vine in the same family as peas and beans. As a legume, kudzu helps fix nitrogen in the soil, but its threat to the environment far outweighs its benefits. Kudzu kills trees and other plants by smothering and choking them with its fast-growing vines, and as the heavy vines engulf trees or shrubs their weight can actually break or uproot trees.

A kudzu vine can grow as much as a foot per day and sixty feet during a growing season. The roots of kudzu are large and fleshy, with a tap root that can be more than seven inches in diameter and more than six feet long. As many as thirty vines will spread from one kudzu root crown.

The roots of an established kudzu vine can weigh as much as 400 pounds, making kudzu difficult to eradicate by digging it up. In addition, the plants will spread by sending out runners, and vines can take root wherever a node touches the ground. Kudzu vine also produces seedpods containing three to ten seeds, but it can take several years for kudzu seeds to germinate and grow.

In its native environment, kudzu is kept in check by insects that eat the vines. However, these insects were not imported to the U.S. along with the vines. Scientists are currently looking for ways to control kudzu but the plant is resistant to many herbicides, and some herbicides only encourage it to grow better. There are ways to keep kudzu vine in control somewhat, but persistence is necessary.

Even when using a strong herbicide such as RoundUp, it can take at least four and as many as ten years of repeated treatments to kill a kudzu vine. Apply herbicides when the vines are actively growing. The kudzu vine and foliage do not actively grow in the winter and are killed off by a frost. But the plant will continue to grow from the sturdy roots in the spring, and this is a good time to begin the process of eradicating kudzu.

Mechanical means of controlling kudzu are often more effective than herbicides, but they are more time consuming. Vines can be mowed down just above ground level every month or two during the growing season. Repeated cutting of the vines will exhaust the plant and it will eventually give up.

But when using this method of kudzu control, all of the plant material must be removed to prevent the vines from taking root and regrowing. The cut vines can be fed to livestock, burned completely, or sealed within plastic bags and buried in a landfill.

Kudzu can be kept in control if goats or cattle are allowed to graze on it. Constant grazing will eventually weaken the plants and rid an area of kudzu. If a kudzu-covered field is intended to be used for perennial fodder, the cattle must occasionally be relocated to another area to allow the kudzu vines to grow back.

Kudzu vine isn’t all bad news. It does have some redeeming qualities. In addition to making excellent fodder for cattle and goats, the plant also controls erosion. The rubbery vines can be used for basket weaving, and basket makers can find an almost endless supply of this raw material for their craft. Fiber from kudzu vine is referred to as ko-kemp and it can be used to make paper and cloth.

Kudzu vine may have become a permanent fixture in the Southern landscape. We can learn to keep it in control but we may never be completely rid of it. We may have to learn to live with kudzu, but make sure to keep the windows closed at night so the vines don’t come into the house.

Questions? I do my best to answer all questions on my blog…

How to Plant Kudzu

Kudzu is a fast growing vine native to China and Japan and was introduced into the United States in the late 1800s as fodder for livestock and to prevent soil erosion. In the southern part of the United States, kudzu is known as “the vine that ate the South” and efforts are made to eradicate it. Kudzu, however, does have its uses. For instance, herbalists use it to treat high blood pressure and menopausal symptoms. Some people also make jams and jellies from kudzu. For these reasons, you may decide that you want to plant some kudzu for your own use.

Pick a planting site away from buildings and trees. Kudzu can grow at least 1-foot per day in sun or shade, and the vines can grow to be 100-feet long. Do not plant it near anything that it can climb, such as trees and buildings, because it can cover them in a very short period of time.

Clear out a plot of ground with a rake or tiller. There is no need to amend the soil or apply any fertilizer or to even clear the ground that well. Kudzu will grow anywhere in any type of dirt and smother anything in its way.

Toss a piece of vine in the middle of the planting area. That is all you have to do. It also does not really matter how big a piece of the vine you use, though a piece 6 to 12 inches long will work just fine. The kudzu will take hold without having the vine actually stuck in the dirt.

Water a little. After throwing your piece of kudzu vine on the ground, just give it a quick spray with the hose. It really needs hardly any water at all to take root.

It was an invasive that grew best in the landscape modern Southerners were most familiar with—the roadsides framed in their car windows. It was conspicuous even at 65 miles per hour, reducing complex and indecipherable landscape details to one seemingly coherent mass. And because it looked as if it covered everything in sight, few people realized that the vine often fizzled out just behind that roadside screen of green.

And that, perhaps, is the real danger of kudzu. Our obsession with the vine hides the South. It veils more serious threats to the countryside, like suburban sprawl, or more destructive invasive plants such as the dense and aggressive cogon grass and the shrubby privet. More important, it obscures the beauty of the South’s original landscape, reducing its rich diversity to a simplistic metaphor.

Conservation biologists are taking a closer look at the natural riches of the Southeastern United States, and they describe it as one of the world’s biodiversity hotspots, in many ways on par with tropical forests. E.O. Wilson, the American biologist and naturalist at Harvard, says the central Gulf Coast states “harbor the most diversity of any part of eastern North America, and probably any part of North America.” Yet when it comes to environmental and conservation funding, the South remains a poor stepchild. It’s as if many have come to view the Southeast as little more than a kudzu desert. A recent study in the Proceedings of the National Academy of Sciences reports that while vulnerable species are primarily in the Southeast, most lands protected as federal and state parks are in the West. Tennessee, Alabama and northern Georgia (often considered centers of the kudzu invasion) and the Florida Panhandle are among the areas that the authors argue should be prioritized.

In the end, kudzu may prove to be among the least appropriate symbols of the Southern landscape and the planet’s future. But its mythic rise and fall should alert us to the careless secondhand way we sometimes view the living world, and how much more we might see if we just looked a little deeper.

Southeast Exotic Pest Plant Council Invasive Plant Manual

Common Name: Kudzu

Scientific Name: Pueraria montana (Lour.) Merr.

This aggressive vine can grow 60 feet per year forming a continuous blanket of foliage. This massive covering often chokes out competing native vegetation that provides food and habitat for native animals. The result is a large-scale alteration of biotic communities. Kudzu is also a problem in forest agriculture and landscaping. It belongs to the Fabaceae (Pea or Bean) family.

Height: Trailing or climbing semi-woody, perennial vines reach 30 m (98 ft) in length.

Roots: Kudzu roots typically reach a soil depth of 1-3 m (3-9 ft) and are capable of storing large amounts of carbohydrates. Roots are tuberous, up to 17.8 cm (7 in) in diameter.

Stem: First year vines are pubescent and may reach 1.3 cm (0.5 in) diameter. Old vines are fibrous, relatively soft, and may reach a diameter of 10 cm (4 in).

Leaves: Foliage is alternate and compound (trifoliate) with leaflets up to 10 cm (4 in) across. Each leaflet is entire or deeply 2-3 lobed with hairy margins. Foliage drops after the first fall frost.

Flowers: Kudzu plants do not usually flower until their third year. Flowers are purple, fragrant, about 1.3 cm (0.5 in) long, produced in long racemes, and resemble pea flowers in shape. Blooms July-October.

Fruit: Three hard seeds are contained in flat, 5 cm (2 in) long, hairy pods. Matures September-October.

Life History

Kudzu is a leguminous perennial actively growing from early summer (May) until the first frost. Sexual reproduction is rare, however seeds have been collected in the Great Smoky Mountains National Park and sprouted in a laboratory dish. Kudzu establishes plants by forming roots at nodes where the vines come in contact with the soil. These roots enlarge to form new crowns. Vines grow rapidly- increases of 15 m (50 ft) in a single season are not uncommon. Roots can penetrate the soil to depths of 3 m (9 ft).

Origin and Distribution

A native of Asia, kudzu was introduced into the United States at the Philadelphia Centennial Exposition in 1876. By 1900 kudzu was available through mail order and sold mainly as an inexpensive livestock forage. The Soil Erosion Service (later renamed the Soil Conservation Service) distributed approximately 85 million seedlings starting in 1933 in an effort to control agricultural erosion. In 1953 the USDA removed kudzu as a cover plant and listed it as a common weed of the South in 1970. It is estimated that kudzu now covers seven million acres in the southeast. Distribution is as far north as Pennsylvania, Illinois, and Connecticut and from eastern Texas to central Oklahoma in the west. The largest infestations are found in Mississippi, Alabama, and Georgia.

Similar Species

Kudzu may be confused with other three-lobed legumes such as dollar leaf (Desmodium rotundifolium ). Distinguishing features of kudzu include: densely pubescent young stem, ovate/trifoliate leaves, and highly invasive characteristics often seen as large areas of contiguous cover. Hog peanut (Amphicarpaea bracteata ) may be mistaken for young kudzu vines, but it does not have pubescent stems or climb extensively into tree crowns.

Habitat


Photo by David J. Moorhead


Photo by Kerry Britton


Photo by James H. Miller


Photo by Ted Bodner

Kudzu grows well under a wide range of environmental conditions, although greatest growth is achieved where winters are mild (40-60°F), summer temperatures rise above 80°F, and rainfall is abundant (101+ cm ). Kudzu can grow in nearly any type of soil (e.g., acid soils, lime soils, lowlands with high water tables, and over heavy subsoil), and where winter soil temperatures remain above -25°F. Large roots allow plants to survive in fairly dry climates and drought conditions. Ideal conditions are moist to well drained and acid to neutral soils (4.5-7.0 pH). New growth may exceed one foot per day . Forest edges or disturbed areas, such as abandoned fields and roadsides, are preferred habitats. Kudzu can persist on the floor of a closed canopy forest; the vines grow up trees toward light and take advantage of any openings.

Management Recommendations

Mechanical Control

Grubbing: Using a pulaski or similar digging tool, remove the entire plant, including the taproot. Removed vegetation should be destroyed by burning or bagging. Because many roots exceed 1.8 m, eradication by this method is very difficult and should be considered primarily for small initial incursions.

Cutting: Vines and runners are chopped just above the ground level, and the pieces destroyed. Early in the season, cutting is repeated at two-week intervals, to weaken the crown and prevent resumption of photosynthesis. Later in the season, when the stored energy in the taproot has been reduced, the interval between cuttings can be extended. Cutting does not typically kill roots and should only be used to control the spread of kudzu.

Herbicidal Control

Cut Stump Method: Use this method in areas where vines are established within or around non-target plants or where vines have grown into the canopy.

    Glyphosate: Cut the stem 5 cm (2 in) above ground level. Immediately apply a 25% solution of glyphosate and water to the cross-section of the stem. This procedure is effective at temperatures as low as 40°F, and may require a subsequent foliar application of glyphosate.

    Triclopyr: Cut the stem 5 cm (2 in) above ground level. Immediately apply a 25% solution of triclopyr and water to the cross-section of the stem. This procedure remains effective at low temperatures (<60°F) as long as the ground is not frozen. A subsequent foliar application may be necessary to control new seedlings.

Foliar Spray Method: Use this method to control large populations. It may be necessary to precede foliar applications with stump treatments to reduce the risk of damaging non-target species. After the stems and leaves have been brought under control (i.e., all above ground portions of the plants have been effectively treated) further treatment should follow the Root Crown Method.

    Glyphosate: Apply a 2% concentration of glyphosate and water plus a 0.5% non-ionic surfactant to thoroughly wet all foliage. Do not apply so heavily that herbicide will drip off leaves. Glyphosate is a non-selective systemic herbicide that may kill non-target partially-sprayed plants. Ambient air temperature should be above 65°F.

    Triclopyr: Apply a 2% concentration of triclopyr and water to thoroughly wet all foliage. Do not apply so heavily that herbicide will drip off leaves. A 0.5% concentration of a non-ionic surfactant is recommended in order to penetrate leaf cuticle. Ambient air temperature should be above 65°F.

Root Crown Method: Follow the young or resprouting stem of the plant to the root. Dig and cut into the root crown using a pulaski or similar tool. Apply a 50% glyphosate solution or 50% triclopyr solution to the main root crown and any below ground runners.

Bibliography

Alabama Forest Products. Convert kudzu to timber in one year? New control methods look promising. Alabama Forest Products 17(10):10, 12, 14, 16; 1974.

Chappell, W. E.; Link, M. L. Kudzu control on Virginia highways. Proceedings of the 30th Annual Meeting Southern Weed Science Society; 1977.

Dickens, R.; Buchanan, G. Influence of time of herbicide application on control of kudzu. Weed Science 19(6):669-671; 1971.

Edwards, M. B.; Miller, J. H. So you want to get rid of your kudzu. Alabama Forests Magazine, March-April, 11-12; 1983.

Edwards, M. D.; Gonzalez, F. E. Forestry herbicide control of kudzu and Japanese honeysuckle in loblolly pine sites in central Georgia. Proceedings of the Southern Weed Science Society (39th) 272-275; 1986.

Edwards, M. B. A herbicide test for kudzu Pueraria lobata control in central Georgia. Georgia Journal of Science 40(12):10; 1982.

Fears, R. D.; Frederick, D. M. Kudzu control on forest planting sites. Proceedings of Southern Weed Science Society 30:260; 1977

W. S. Kudzu. Proceedings of the 22nd Annual Meeting of the Southern Weed Science Society, 310. Abstract; 1969.

Hern, L. K. Herbicide treatment offers promise in the control of kudzu. Forest Farmer 1(7):17-18; 1982.

Michael, J. L. Some new possibilities to control kudzu. Proceedings of the Southern Weed Science Society 35:237-240; 1982.

Michael, J. L. Pine regeneration with simultaneous control of kudzu. Proceedings of Southern Weed Science Society 39:282-288; 1986.

Miller, J. H. Testing herbicides for kudzu eradication on a piedmont site. Southern Journal of Applied Forestry 9(2):128-132, 1985.

Miller, J. H. Kudzu eradication trials with new herbicides. Proceedings of the Southern Weed Science Society 41:220-225; 1988.

Miller, J. H. Kudzu eradication trials testing fifteen herbicides. Proceedings of the Southern Weed Science Society 39:276-281; 1986.

Miller, J. H.; Boyd, E. Kudzu: where did it come from and how can we stop it? Southern Journal of Applied Forestry 7(3):165-169; 1983.

Miller, J. H.; Boyd, E. Hazards of applying kudzu control herbicides. USDA Southeastern Forest Experiment Station; 1983. Romm, H. J. The development and structure of the vegetative and reproductive organs of kudzu. Iowa State College Journal of Science 27(3):407-419; 1953.

Rosen, A. Feasibility study: Eradication of kudzu with herbicides and revegetation with native tree species in two national parks. NPS, Research/Resources Report SER-59; 1982.

Shurtleff, W.; Aoyagi, A. The book of kudzu. Brookline, MA: Autumn Press; 1977.

Smith, A. E. Kudzu control in nonforested areas with herbicides. Resources Bulletin of the University of Georgia Agricultural Experiment Station: Athens, GA 591: 8; 1990.

Leave a Reply

Your email address will not be published. Required fields are marked *