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Eurasian Watermilfoil is most often dispersed by water birds and boats. It spreads easily through a process called fragmentation, in which the plant breaks into small pieces. These small pieces (spread by birds and boats) form roots and become a new plant. In one year, a single wisp can multiply into 250 million new plants.

Potential Harms:

Eurasian Watermilfoil grows on the surface of waters creating thick mats, choking out native plants, reducing plant diversity, and affecting fish and wildlife habitats.  Milfoil also clogs pipe intakes used for irrigation and power facilities, and invades fish spawning habitats. In the height of the summer when mats are thickest, mats may also inhibit swimming, boating, and fishing.

Identification:

• Eurasian watermilfoil is most easily identified by its feathery leaves.
• Beware! Identifying different types of milfoil can be a difficult task even for experts. A DNA test is required to be certain.
• Eurasian Watermilfoil has a thinner stem than other species and as result can be distinguished in a few ways: it typically has 12 or more pairs of leaflets on each leaf and when taken out of the water the leaves collapse around the stem.

Prevention:

Although herbicides, harvesting, and bottom screening may help control the spread of Eurasian Watermilfoil, eradication is expensive and not very effective.  Once milfoil finds its way to a lake, there is no way to completely get rid off it. The best way to keep waters clean is to prevent its spread by cleaning the fragments off of boats.  It takes just one fragment to create an invasion.

Also if spotted, report to authorities. The Montana Noxious Weed Trust Fund offers bounties for new invaders.  $100 for the first verified sighting, $50 for all sightings after.  Contact your local weed district to report.

Links to more info on Eurasian Watermilfoil:

http://fwp.mt.gov/fishing/guide/ANS/plants.html#eurasianwatermilfoil

http://www.ecy.wa.gov/programs/wq/plants/weeds/milfoil.html