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Myriophyllum spicatum

Biological Category 
Species Type 
Aquatic Invasives
LHPrism Status 
Tier 4 - Widespread
Key Characteristics 
Feather like whorled leaves; long and soft and deeply divided.
Flower spikes above the water with reddish flowers arranged in 4-flowered whorls along the spike.
Grows with long branching stems that are submerged and rooted into substrate.

Vertical Tabs

Impacts of this species 

Eurasian water-milfoil has adapted to a variety of water conditions and has established colonies in lakes, ponds, reservoirs, and low energy areas of rivers and streams. It can grow in brackish water as well as fresh water, and has an affinity for areas that have been exposed to disturbances, such as nutrient loading, intense plant management and excessive motorboat use. This plant spreads rapidly with multiple means of reproduction. It propagates from seeds, roots and stem fragments, often developing roots before separating from the parent plant. It successfully competes against native plants by its means of reproduction and its ability to grow quickly, stealing sunlight and space from other plants. These plants can also alter the hydrology of waterways, leading to decreased dissolved oxygen content, increased temperatures and pH. They can also have large impacts on recreation, damaging mechanisms of boats, reducing recreational value of nearby locations, and also clogging waterways utilized by facilities.