Early after it's founding the Coalition planned to experiment with fences as kudzu barriers, as this June 2005 photograph taken at our test site demonstrates. In this case, the idea was to use inexpensive polyethylene sheets as barriers that are too slippery for kudzu to climb over. Experiments were undertaken with both black and white sheets.

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Such barriers are indeed effective against kudzu. July 2005.

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Tests of fences covered in polyethylene sheets have a dual objective: Kill the covered kudzu, and prevent growing kudzu from crossing the fence. The photograph shows how side-by-side comparisons were made of the effectiveness of black and clear sheets. May 2005.

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Clear sheets split due to degradation by the ultraviolet light (UV) in sunlight. Black sheets do not split because UV is blocked by the black colorant (carbon black). This light-blocking characteristic halts photosynthesis in underlying kudzu leaves, and kills them quicker. The splitting of clear sheets plagued all experiments involving clear sheets. July 2005.

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The splitting problem occurred when using polyethylene sheets for barrier fences. The Coalition decided to test Callahan's Kudzu Barrier Fence. The fabric material for the fence should better resist UV degradation and tearing, and offer less wind resistance. For now we prefer to treat Coalition installations that use this product as "experiments", instead of urban site-specific treatments.

The first photograph (March 2006) shows a relatively short version of the fence installed at the Coalition test site in place of a polyethylene sheet fence used last year (see the white sheet fence on the first photograph at the top of this page). Several inches of fence fabric are buried in a trench dug along the bottom of the fence, the depth acting as a barrier to kudzu vines growing under the fence. The second photograph shows the same fence successfully holding back kudzu at the peak of the growing season (June 2006). Unfortunately, Johnson grass grew taller than the fence. It became necessary to stomp-down the grass by foot to prevent kudzu from using the tall grass as scaffolding to climb across the fence!

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A different version of this fence was built at the Spartanburg Humane Society. This fence lies parallel to a property line, over which kudzu arrives from an adjacent lot. Slightly different construction methods are used for each fence to learn which is most cost effective and easiest to install. Shown left to right are Coalition volunteers Lou Adams and Paul Savko. April 2006.

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This photograph demonstrates what happens when a fence has some feature that a vine can "grab" and climb. Although the vine shown is not kudzu, it could just as easily have been kudzu in this case. And although kudzu cannot wind around an object larger than about 8 inches in diameter, it can piggyback onto other vines which can climb such an object. This is typically how kudzu climbs trees. July 2006.

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Jack Callahan visits the Coalition at least once each year. During his 2009 visit, he mentioned a possible substitute for the 50% shade cloth (see above) that we use as kudzu barrier on fences. Jack said that aluminum window screen material might be less expensive and last longer. The new screen is shown in the photograph mounted on a chain link fence at Spartanburg Humane Society. Coalition volunteer Paul Savko attached the screen using plastic ties. It is too early to render a judgment about the screen's effectiveness as a kudzu barrier. December 2009.

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Fences: The Bottom Line

  1. Properly designed fences are effective kudzu barriers. They must be at least 5' high, and have no features (on the kudzu side of the fence) smaller than about 8" in diameter that kudzu can wrap around and climb. Burying the fence material at least 4" is also necessary.
  2. Some monitoring is required to make certain kudzu has not overcome the barrier. And control might be necessary in the form of eliminating kudzu scaffolding from the vicinity of the fence, or turning kudzu vines away from the fence (redirection), so that a buildup of vines does not overwhelm the barrier.
  3. One simple way to maintain fence effectiveness is to occasionally "walk down" kudzu and tall plants near the fence. Compressing plants by foot next to the fence increases the vertical distance kudzu vines must "reach" to climb over the fence.
  4. Fences that are effective kudzu barriers cost from $4 to $5 per linear foot.
  5. Construction of a fence is not always possible by the general public due to material availability and costs, necessary skills, or siting difficulties (rough or rocky ground, for example).
  6. Construction of a fence is not always desirable in an urban setting due to aesthetics: Its appearance might not be appropriate in a residential area, for example. Typical fences that are attractive to homeowners are not satisfactory kudzu barriers. The most "attractive" fence material is 50% shade fabric, which also offers lower wind resistance than a solid sheet.
  7. Click here for alternative kudzu control methods for small property owners.