logo150 Hamilton County Soil & Water Conservation District  

Japanese Knotweed

Hamilton County Distribution

  • Roadsides
  • Stream banks
  • Disturbed locales


  • Cascading flowers bloom in the summer
  • Stems are hollow and notched
  • Leaves are leathery and heart shaped


  • Spreads by rhizomes that stretch long distances through soil
  • Early spring emergence
  • Dense stands displaces native plants
  • Causes erosion along stream banks
  • Dormant stems remain during the winter and create a fire hazard


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Invasive Plant Best Management Practices for Landowners

1. A permit must be obtained from the Adirondack Park Agency if the invader to be controlled is located in or within 100 ft of a wetland on public or private land.

2. Private property owners are allowed to apply general use herbicide products (Roundup Pro Max, and Roundup Pro Concentrate) on their own property for invasive species control. In all instances the herbicide product label is the law and must be read and followed accordingly.japaneseknotweed

3. All herbicide applications in or around surface waters or wetlands should be made by a New York State certified pesticide applicator.

4. Spot treatments to individual plants using a back pack or hand sprayer, wick applicator, cloth glove applicator, stem injection system, herbicide clippers, etc. are allowed for use during herbicide applications.

5. During manual management, bag all plant material in a heavy duty garbage bag and leave outside in the sun for a couple weeks. Dispose of bags in a landfill. For woody invasive shrubs, excavate or dig up while not in fruit, and dry with roots propped upwards for a few weeks. Burn dead material or use to construct brush piles for wildlife habitat improvement.

6. To prevent the spread of invasive plants, manage when plants are not in seed. All management equipment should be thoroughly rinsed off with water before the next use.

7. If you have removed invasive plants from your property and would like to replace them with native alternatives, contact the Hamilton County Soil and Water Conservation District for recommendations.

8. Be persistent as plants may grow back. For larger infestations, complete elimination may take several years of consistent management.

The District’s accomplishments would not be possible without the support of the State of New York, Hamilton County, and FLLOWPA.