How did milfoil get to New Hampshire?

Milfoil, specifically Eurasian watermilfoil, was likely introduced to New Hampshire and other parts of North America through various means, including contaminated boat trailers, aquatic plants sold for ornamental purposes, and water gardening supplies. Its spread is often exacerbated by recreational boating and fishing activities, which facilitate its transfer between water bodies. Once introduced, milfoil can rapidly proliferate, leading to significant ecological and recreational challenges in affected areas.