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Washington State Noxious Weed Control Board |
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Class B Noxious Weed
Eurasian Watermilfoil
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Plant family:
Haloragaceae
Year listed:
Native to: Europe,
Asia and Northern Africa.
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Why is it a noxious weed? |
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Eurasian watermilfoil is another ornamental aquatic
plant that has escaped cultivation. Infestations can alter aquatic
ecosystems. It forms dense mats that shade out other native aquatic
plants, inhibits water flow, and recreational activities.
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How would I identify it? |
| General Description:
Eurasian watermilfoil is a submersed aquatic plant. Leaves:
Flowers:
Stems:
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How does it reproduce? |
| Eurasian watermilfoil spreads mainly by stem fragments. | ||
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Where does it grow? |
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| Eurasian watermilfoil is highly adaptable, it is found in streams, ponds, lakes and ditches. | ||
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What is the distribution in Washington State? |
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How do I control it? |
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General control methods: Eurasian watermilfoil control can be difficult. Since it spreads by stem fragments, care must be taken to ensure entire plant is removed if mechanical methods or hand pulling is used. Cultural: Small infestations may be able to be controlled with the use of an opaque fabric that blocks light from the plant. Hand pulling may be employed, but entire plant must be removed or it will resprout. Herbicide: Because herbicide availability and regulation differ between States, as well as between countries, we recommend the Washington Department of Ecology web site for information on aquatic weed management and herbicides. Mechanical: Not advised unless area is entirely invaded by plants. Otherwise, mechanical methods may increase infestation. Biological: Triploid grass carp will eat Eurasian watermilfoil, but it is not very palatable and is not preferred food for the grass carp. Research into other biological methods is being done. |
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Are there plants that may be confused with Eurasian watermilfoil? |
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| There
is a
native watermilfoil (myriophyllum sibericum) that may be
confused with Eurasian watermilfoil. Eurasian watermilfoil also
looks similar to
Parrotfeather
(Myriophyllum aquaticum), a Class B noxious weed in Washington.
If you need help with identification, please contact your
county weed coordinator.
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For more information |
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For more information, download our
Written Findings.
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Last updated October 01, 2008