Types

• Vinegar is an acidic acid solution, available in a concentration of 5 percent and 20 percent. Household vinegar, the 5 percent solution, is available at grocery stores. A 20 percent concentration is more difficult to find because of its toxic properties. This type of vinegar is available at some garden stores or a chemical supplier.
  
  

Process

• The U.S. Department of Agriculture reports that the 20 percent solution kills 85 percent of weed growth, making it a better option for killing the weeds around cattails. Spray the vinegar directly on the weeds, and avoid spraying the cattails to prevent damage.
  
  

How it Works

• Weeds pull vinegar into their cellular system, similar to pulling in moisture. The acid in the vinegar causes damage to the plant cells, eventually killing the weed.
  
  

Considerations

• Cattails grow in a marshy area, which may reduce the effectiveness of the vinegar if you spray near the base of the plant. Apply the vinegar to the leaves and stem of the weeds to increase the absorption rate.