Frost kills kudzu foliage, and kudzu is rare or sparse in climates with freezing temperatures. Would freezing the crown kill the kudzu plant? In these experiments freezing is tested as a possible treatment. The freezing treatment was tested in cases where a portion of the crown was visible to give the treatment a better chance of working: It is difficult enough trying to freeze something in the open air on a hot summer day, let alone freeze something that is buried below asphalt or concrete!

This photograph shows a handheld medical device charged with liquid nitrogen applying a stream of very cold gas to a kudzu crown (circled in red) embedded in a crack in asphalt. Note the glove used to protect the hand! The crown is not removable without breaking open asphalt, hence the attempt to kill it by freezing. The device is similar in function to an aerosol can, with a trigger and nozzle. Dermatologists use these bottles to freeze pre-cancerous cells. Dr. Elizabeth Dunlavey, Spartanburg Dermatology & Skin Surgery Clinic, graciously provided the bottle and refills for us. All photographs May 2006.

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Here is a closeup of the freezing procedure for a different crown, circled in red, in asphalt. Different treatment times are part of the experimental protocol, as it is difficult to know to what depth the crown is frozen. The results of these experiments were not promising. Perhaps this is not surprising because kudzu is found in northern states where below-freezing winter temperatures are common.

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Freezing: The Bottom Line

  1. Has potential value whenever kudzu root crowns are inaccessible (under asphalt, concrete, brick, or stone).
  2. Liquid nitrogen is expensive and requires special tanks.
  3. Liquid nitrogen in the hand held bottles pictured above has a useful life of less than eight hours when unused, so refills are required each day. The liquid is completely exhausted after only treating a few crowns.
  4. Carrying small bottles into a kudzu infestation to attack only a few crowns is generally less efficient than other approaches.
  5. Normal sized tanks of liquid nitrogen are too large and heavy to easily transport and move around outdoors. They are safety hazards due to their weight and the possibility of breaking the pressure valve if the tank is accidentally dropped or knocked over.
  6. There is one advantage over the propane torch treatment when attacking kudzu crowns that are growing up through asphalt, and in spaces between concrete slabs: There is no danger of fire.
  7. The Coalition is not actively using or further investigating this method.
  8. Click here to see alternatives to freezing crowns for kudzu control for small property owners.