Eurasian watermilfoil (Myriophyllum
courtesy of Debbie Bowen)
Scientific Name: Myriophyllum spicatum
, (Eurasian water
: Perennial. The weed is usually found under
This plant was introduced to North America in the 1940's.
: Usually has 9 to 21 leaflets. Leaves will
grow up to 2.54 cm long and are very fine and needle like. Leaves
when they are out of water whereas they are like feathers when they are
in the water. The leaves are usually divided into 9
leaflets, and the end of the leaves has a blunt tip. Some leaves
in a twirl pattern around the stem. When the leaves are
water they lose their stability and collapse around the stem. (2,
: Stout, slender, and roots extend from the
stem in many places.
Stems can be 3 meters or longer in length. The
stems are able to produce new plants by fragmentation (breaking off).
stem is usually pale pink to red to reddish brown and has feathery
: The flowers of this weed radiate from the swirling
form closely to the leaves. The growing tips at the end of the
plant are bright red or pink color. The flower is in a spike form
and has small, yellow four petaled flowers in clusters on the end of
twice as wide as the stem. The spike on the flower is about 5-20
cm long. The flowers are above the water. (2, 3, 6)
: The roots are fibrous, and are at the base of the
plant and on the segments of the stem. (2, 7)
: The plant spreads and reproduces by
which is asexual, and also by sexual reproduction (flowers, fruit and
: The seeds are usually about 2-3 mm long and come in
off of the weed. (3, 2)
Small segmented capsule
that has fours seed inside of it. (7)
Habitat and Range
: Eurasian water milfoil is an aquatic weed.
This weed is generally found near the surface or just below it.
It grows best in fine grained inorganic sediments
Some ways to keep Eurasion water milfoil from
spreading to other bodies of water is to
check all the equipment (boats, motors, trailers,
fishing gear, ect.) that was used in infested waters and
remove all aquatic plants when leaving the lake or river. Plants can be
hand pulled to get rid of really thick areas of the weed. This,
however is not very effective for long term solution because fragments
of the plant could be left behind. Mechanical harvesters can also be
used to get rid of very large infestations, but like hand pulling its
not an effective long term solution. (6)
Some herbicides can
be used on this plant (in water). Check with your local weed
coordinator or extension agent and read the label
known biological control so far is the weevil
adult weevils eat Eurasion water milfoil and the female weevils lay
eggs on the top of the weed, and when the eggs hatch the larvae burrow
holes throughout the stem of the plant, casuing a lot of damage. (6)
Eurasian water milfoil
has now (2008) invaded Montana in the Clark Fork River, near
Noxon. [Breitenfeldt, Todd].
1. Debbie Bowen. "Eurasian
water milfoil: fact sheet." MNSG. Feb. 11, 2004. Minnesota Sea Grant.
Identification." Adirondack Park Invasive Plant Program. . Aquatic
Invasive Plant Project. 3/19/04, http://www.adkinvasives.com/Aquatic/PlantID/EMilfoil.html
3. "Eurasian Water milfoil: Myriophyllum spicatum." Virginia Tech
Weed Identification. . . 3/10/04, http://www.ppws.vt.edu/scott/weed_id/mypsp.htm
4. Colette Jacono. "Eurasian water milfoil." . 3/16/04. .
5. "Minnesota DNR."
Eurasian water milfoil. . . 3/18/04, http://www.dnr.state.mn.us/exotics/aquaticplants/milfoil/index.html
6. "Eurasion Water Milfoil (Myriophyllum spicatum
Department of Natural Resources. 2/23/09, [http://www.dnr.state.wi.us/invasives/fact/milfoil.htm
7. "Eurasion Water Milfoil." Montana Noxious Weed. 2/23/09, [http://agr.mt.gov/weedpest/Category3/EurasianWaterMilfoil.htm
By: Zac and Layne.
Updated By: Travis Sizemore, 2/8/05.
Updated By: Megan Enriquez, 2/25/09
Back to Weed ID