Eurasian Milfoil (Myriophyllum spicatum)

Eurasian Milfoil is a submerged aquatic plant native to Europe, Asia and North Africa. It has whorled leaves that are up to one inch long that appear to be clipped on end and are limp when out of water. It can grow up to 10 feet in height and exhibits a reddish shoot near the surface. It forms dense mats of tangled plants in lakes and ponds. When fragmented, a small piece of the plant can float away, re-root and begin a new colony, allowing it to quickly spread throughout a lake or pond. As a result, native plants are crowded out, fish habitat is degraded and recreational activities are impaired. 

Eurasian Watermilfoil was first discovered in Lake George in 1985. By 1998, the aquatic plant had spread to 127 known sites, 31 of which contain dense growths. In 2001, monitoring of milfoil, conducted by DFWI, revealed two new milfoil sites, bringing the total number of sites with milfoil to 141. Several methods to control milfoil in Lake George have been used including hand pulling and matting; however, no large-scale control for moderate to high-density areas has been used to date. 

http://www.lakegeorgeassociation.org/html/eurasian_watermilfoil.htm, http://www.thefundforlakegeorge.org/state-of-the-lake-01.htm