If milfoil grew on dry ground the way it grows under water we likely would blast it with any herbicide even close to safe. Imagine, wide swaths of open land rendered unusable and impassable to people or their vehicles by a tall-growing plant, a noxious weed so prolific it reproduces wherever bits and pieces hit the ground. That is happening in our rivers and lakes.
Eurasian watermilfoil, as it is properly known, is as invasive as an invasive species can be. It is very easily spread, usually by unclean boat trailers. Chopped bits anchor and grow in shallows, rise to the heights, and form ugly mats on the water’s surface. Wherever it grows, the aquatic ecosystem is radically changed, rapidly. Boating, waterskiing, tubing, fishing and other forms of recreation become difficult or impossible, and even help spread the plant.