Milfoil is an invasive, non-native plant that thrives in clear, nutrient rich water.


    • Milfoil is present in a growing number of water bodies, in both northern and southern areas of the state.
    • Some infested water bodies have shorelines in more than one town.
    • It is difficult to predict exactly where outbreaks will occur.
    • The species of milfoil that is found in New Hampshire is problematic in only a handful of other states, while the Eurasian milfoil species is the more common nuisance species across the country (so nationally funded research is focused on that species).


    • Property values decline when thick milfoil growth prevents swimming and use of waterways by small boats.
    • Fish, including game fish, decline when milfoil growth changes the chemistry of the water (e.g. reduced oxygen).  [Bass can thrive in areas with native, non-invasive species.]
    • Without the clear waterways which New Hampshire depends on for its tourist economy:
      • The significant amounts of money invested in marketing the state will be wasted.
      • Fewer visitors to state and fewer dollars spent on tourism.


    • Seed heads rise above the surface of the water and release seeds which travel to new locations.
    • Cuttings (caused by wind and human activity) can grow roots, starting new patches.
    • Milfoil can be spread from water body to another when fragments are present on the hulls and engines of boats of any size.


Eradication Methods

Unsuccessful Methods

  • Milfoil has no natural enemies in this area.
  • Pulling milfoil breaks it apart, allowing fragments to float away to establish new plantings.
  • Places where herbicides have been used, (Wolfeboro’s Back Bay, for example), have experienced prolific re-growth when applications are stopped.
  • Draining water bodies is ineffective as milfoil can survive without water.

 Best Practices

  • Diver assisted suction harvesting, as practiced onSquamLake:
    • Two boats dedicated to milfoil eradication work full time during warm months.  Each has a driver and a diver.  Volunteers follow behind to scoop any loose fragments that float to the surface.  [Mr. Levine manages this program for the Squam Lakes Association.]
  • Efforts must be repeated on an ongoing basis.

Volunteer Efforts

    • Training is inconsistent or lacking and may result in accelerating spread.
    • Coverage is fragmented.
    • Out of pocket expenses are incurred by volunteers.

Cost of Eradication

    • Freedom has spent over $100,000 since 1992.
    • There are currently about thirty water bodies with identified infestations that have not been treated.
    • According to a survey of milfoil control funding  

      sources from the Ossipee Lake Alliance, a total of 

      $2,650,027 was spent from 2009 to 2012. Of that, 82 percent 

      of the funding came from municipal and private 

      sources, with the state picking up only 18 percent — or 

      $484,462 — of the milfoil control effort costs. In that four-year period, municipalities 

      allocated, mostly through warrant articles approved 

      by voters, $1,278,904, and private funding, including 

      money raised by lake associations, tallied $866,650, 

      or 34 percent.


    • In New Hampshire, water bodies belong to the public.
    • The State promotes water based tourism, but provides limited funding for maintaining that resource.
    • When the state does not take responsibility, it falls to towns which then increase their taxes.  Towns are unable to address the problem individually and some bear a disproportionate burden.
    • The Department of Environmental Services runs the state’s milfoil program.
    • The program is funded on a statewide basis but administered/managed locally by municipalities or organizations.


    • Tri-town Milfoil Committee [Ossipee, Freedom, Effingham]
      • Members appointed by select boards
      • Dissolved.
    • Fish & Game’s role?
    • Individual alliances, such as the Ossipee Lake Alliance
    • NH Lakes Association
    • Milfoil Coalition
    • UNH Cooperative Extension
      • Through the NH Lakes Lay Monitoring program, educates volunteer lake monitors across the state on reducing the spread of the weed.
      • Confirms the presence of the weed and encourages participation in the DES weed watchers program and the NH Lakes Association Lake Host Boat ramp inspection program.
      • When funding was available, conducted applied research projects investigating biological controls and assisted in designing and evaluating an integrated pest management approach to milfoil control.
      • Demonstrated that clearing shoreline vegetation at the water’s edge increases milfoill’s ability to dominate over native plants as they thrive in direct sunlight.


2014 HB 292

  • An amendment proposes to add $2 to the amount of a boat registration to be dedicated to milfoil prevention and eradication.
  • Focused on broader coverage for mitigation.
  • Will allow more aggressive treatment locally.
  • Passed in both the House and Senate

Other Legislation Needed

    • Education and prevention funding (e.g. increase grants to Lake Host program as well as other opportunities to inform both residents and visitors).

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