Eurasian watermilfoil (myriophyllum spicatum) is an invasive species that made its
way into Minnesota lakes in the late 1980s. This plant can cause many problems
when introduced to a water body that it is not native to. One of the main issues with
Eurasian watermilfoil is that it grows rapidly, which shades out native aquatic
plants so they do not get enough sunlight. Besides making it hard for native plants to
thrive, Eurasian watermilfoil also creates uninhabitable settings for native animals
by changing their nesting and feeding environments.
How to identify:
Eurasian Watermilfoil
Native plants such as coontail and northern watermilfoil are often mistaken as the
invasive Eurasian watermilfoil. The native aquatic plants are beneficial to the
animals and overall environment of the lake. It’s important to be able to spot the
differences between these native plants and Eurasian watermilfoil in order to
properly identify and get rid of the invasive species.
Eurasian watermilfoil has a reddish- or brownish-colored stem, but this can often
vary. While Eurasian watermilfoil has around 12-21 leaflet pairs per leaf, northern
watermilfoil only has about 5-10 leaflet pairs on each leaf. Another giveaway that
your lake weed is Eurasian watermilfoil is if the leaves go limp when taken out of
the water. Northern watermilfoil leaves stay rigid, even when out of the water.
Coontail is another native plant that is often misidentified as Eurasian watermilfoil.
The easiest way to tell the difference between these two plants is by looking at their
leaves. Coontail is usually bushy and forked near the tip, which gives it a Christmas
tree-like appearance. Eurasian watermilfoil’s leaves, on the other hand, have a flat,
feather-like look to them.
What to do:
Eurasian watermilfoil is an invasive species in the United States; to keep it from
spreading, make sure to clean and drain your watercrafts after taking them out of
any body of water. To control already present Eurasian watermilfoil, mechanical
methods such as cutting, pulling, and/or raking can be used to rid an affected area of
the invasive species.