Eurasian Water Milfoil

Eurasian water milfoil is an aggressive invasive aquatic plant and is present in our lake.  See the locations in our lake with with reported sitings (enter Ompah, Ontario in the search bar).  Please take great care.  Fragments broken off by motor boats, fishing lures, or by pulling neighbouring weeds can root and cause the plant to spread. 

What can you do?

  1. You can try to control growth near your shoreline by carefully hand-pulling eurasian water milfoil plants, being careful not to cause any fragments to break off and to get the entire root.  (see below for how to identify this plant.)
  2. If you see floating fragments, carefully scoop them out of the water and dispose of them on land well away from the shore. 
  3. See the Ontario Invasive Plant Council’s  document on best management practices for Eurasian Water-Milfoil.
  4. Report a sighting.  Take a photograph, note the GPS coordinates, and email the information to  We will add the report to the distribution map for Ontario that is available here. 

Eurasian water milfoil can out-compete native aquatic plants and eventually choke off portions of the lake.  Plants have been known to grow in water as deep as 10 metres. 

Not to be confused with the native Northern Water Milfoil, the easiest way to identify Eurasian Water Milfoil is by counting the pairs of leaflets on each leaf.  If there are more than 11 pairs, it’s Eurasian Water Milfoil.  It also becomes limp when out of the water unlike the native milfoil which remains rigid.