Get this great booklet from MSU about Eurasian Watermilfoil
Eurasian watermilfoil is a submersed aquatic plant that forms dense tangled beds that can competitively displace submersed native plant communities, reduce recreational qualities of water bodies, reduce water flow, clog industrial, agricultural, and drinking water supplies, and negatively impact fish and wildlife. If was first reported in Montana in Noxon Reservoir (Sanders County) in 2007. Plants primarily spread through stem fragmentation. Water recreation (primarily boats and boat trailers) is the predominant vector of long distance spread. After prevention, early detection and immediate action to contain and eradicate infestations are the most important management actions for Eurasian watermilfoil in Montana.
Download the booklet from MSU Extension now.