Lac Notre-Dame and Usher Lake Association logo
Lac Notre-Dame and Usher Lake Association

Eurasian Milfoil

Originating in Europe, Eurasian watermilfoil is an invasive aquatic plant that usually grows at depths of 1 to 4 metres and can form a dense carpet on the lake’s surface. According to Environment Canada, “this plant not only pushes out indigenous plant species, but may also be harmful to fish populations by crowding out their spawning grounds.”

Originaire d'Europe, le myriophylle en épi est une plante aquatique envahissante qui pousse généralement à des profondeurs de 1 à 4 mètres et peut former un tapis dense à la surface du lac. Selon Environnement Canada, "cette plante ne fait pas que repousser les espèces végétales indigènes, elle peut aussi nuire aux populations de poissons en évinçant leurs frayères".


  1. Chaque morceau de mauvaise herbe cassé peut se transformer en une nouvelle plante. Évitez les zones du lac infestées par la plante. Les pires tapis sont marqués par des bouées d'association lors des mauvais étés - évitez ces zones avec n'importe quel type d'embarcation.

Each broken-off bit of weed can turn into a new plant. Avoid areas of the lake infested with the plant. The worst mats are marked by Association buoys in bad summers - stay out of those areas with any kind of boat at all.

  • Les résidents du lac sont encouragés à les retirer du lac et à les utiliser comme compost loin du rivage.
  • Milfoil bits may also drift in that have been cut up by boat motors, and lake residents are encouraged to remove them from the lake - use them as compost far from shore.
sign warning stay clear of yellow buoy - restez loins des bouees
  1. Cutting does seem to help, as long as you remove the cuttings. Lake residents who have been consistently cutting the weeds for a few years notice that fewer and fewer appear. Try not to stir up the bottom as you cut - that moves nutrients into the water for the weeds. Raking is not advised at all other than raking your cuttings off the surface of the water.
  1. Stop nitrates from fertizers and phosphates from detergents from entering the lake. These nutrients feed the weeds as well as damaging the overall health of the lake.

History of Milfoil in Lac Notre-Dame and Usher

The Association was founded in 2004 in response to the Eurasian Milfoil explosion in the lakes. The Association received valued advice and assistance from biologist Paul Hamilton of the Canadian Museum of Nature. Mr. Hamilton has continued to support the Lake's efforts by monitoring our water testing results and advising us about important changes in the water quality.

  • Electric cutter history: An electric cutter was purchased before 2008 by the Association, with a financial contribution of $6,400 from the Municipality of La Peche and is stored at Bob Scott’s.

The cutter required mounting on a barge and a team of 10-12 volunteers to manage both the cutter and the manual labour of removing the heavy cuttings from the water. After a few years, as the weed levels naturally declined, & the cutter was no longer used due to the huge amount of effort required to organize a volunteer team, boats, fuel and strong bodies. The barge was destroyed in 2010, as it was stored at Camp Kalalla, and was a danger to the camp.

* The Association did not renew the insurance for the cutter; therefore future users would need to sign a waiver to borrow the cutter and would have to return it in the same condition that they received it in. No one has done so since 2010.