Eurasian Watermilfoil. The pink color and the flowers is a good indicator.
Appearance
Eurasian watermilfoil is a rooted, submerged aquatic plant. The leaves appear green while the stems are white to reddish.
Leaves and Stem
Leaves are feather-like, with four leaves arranged in a whorl (radiating out from a single point) around the stem. Space between whorls along the stem can be a half inch or greater. Each leaf has a central axis with 12 to 21 leaflet pairs. Leaflets are limp when the plant is removed from the water. The stem is typically light brown, but sometimes pink. Tips of the plant are sometimes red or pink in color. Color alone should not be used for identification as it can be highly variable.
Flowers
A small pink flower spike up to four inches long produces tiny yellow flowers. Male and female flowers are found on the same plant.
Seeds
Even though each plant can produce approximately 100 seeds per season, this species is more successful at reproducing via fragments.
Roots
Roots are thin, white, and sometimes form dense clumps underneath the plant.
It's in all of the states except Hawaii.
It's easy to kill with a low dose of Fluridone. It's best to treat the plant in late April to early May because it takes 30-45 days to die. You want to treat it before it sets seeds for that growing year.
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