In addition to contacting us with any questions, one very important action you should take is to verify exactly which species of milfoil you are dealing with.

Differentiating between the various types of milfoil can be very difficult and require an expert. To complicate matters even more, Eurasian watermilfoil can hybridize with at least two of the native North American varieties of milfoil. Sometimes, the only way to definitively identify these hybrids is via genetic analysis.

Regardless, proper identification of your problem plant(s) is key to developing a successful management program. We can help by confirming the identity of the milfoil present in your lake.

One of the most common native species is Northern watermilfoil (M. sibiricum). The first step in confirming that you are dealing with Eurasian watermilfoil as opposed to Northern watermilfoil is to collect several stems from various locations in your lake and count the leaflets. Eurasian watermilfoil will typically have more than 13 leaflets and Northern will usually have 11 or fewer leaflets. Use the photos included here for a guide.

If your digital camera will take good close ups, take a few photos of the plant in your lake, a photo of a few individual stems spread out on a white background, and one or two closeup photos of the leaves and leaflets. Mail or preferably email the photos using the links at left with some details about the waterbody and the problem.

In addition, one of the best ways to determine the type of milfoil you are dealing with is to send us a sample. To do that, collect a few stems from different areas of the lake and cut off the top 6-8 inches. What we are interested in seeing is the terminal growing tip, particularly if there are flower stalks present.

Wrap the moist plants in slightly damp paper towels, put them in a Ziploc bag and squeeze out any excess water and air before sealing it. Take that bag and put it in a second Ziploc bag and mail it to use via overnight or second day delivery. During warm months, try to avoid sending it over a weekend to minimize decomposition.

Please include details about the collection (when, where and who plus contact information) plus a little information about the waterbody (name, location, size, etc.) where the sample was collected. One of our botanists will be glad to identify it for you and in most cases, we will be able to get back to you with the ID and some recommendations in a matter of days.