However, not all Milfoil should be treated equal. There are actually two very different types of Milfoil found in lakes and ponds. Let me explain…

Native and non-native milfoils in the many parts of the United States and Canada today. These are aquatic plants found in freshwater bodies, especially but not limited to lakes. It is quite difficult to visually distinguish between the native and non-native or “spiked” milfoil plants, even for trained professional biologists and naturalists. The plants of the non-native milfoil, like the native, have subsurface feathery and threadlike leaves that are whorled about slender stems and which are usually uniform in their diameters while being aggregated into a subsurface terminal spike. There are tiny flowers that will blossom above the water’s surface in Spring and Summer, and these are located on the floral bracts in the plants’ axils. They may be either four-petaled or they may not have any petals. Below the inflorescence, the stem thickens to the point that it doubles in width further down. Typically, it will also curve so that it lies parallel to the water surf ace.

The non-native milfoil will also bear fruits which resemble nuts and are four-jointed. Now, without the flowers or the fruits being seen, the non-native milfoil is extremely impossible to distinguish from North American milfoil. Sometimes, it can be distinguished by a leaflet count. The spiked milfoil has anywhere from nine to 21 pairs of leaflets on each leaf; North American milfoil usually has anywhere from seven to 11 pairs of leaflets. The aquatic plant called “coontail” often gets confused for milfoil, both native and non-native; however coontail doesn’t have individual leaflets.

The non-native or spiked milfoil will most often be found where there are fine-textured, fertile, and inorganic sediments. It will only be found in nutrient-rich sediments in less fertile lakes, but it will tend to dominate those places because it is highly opportunistic and very well adapted to highly disturbed lake beds, highly used lakes, and lakes that receive much phosphorous and nitrogen from run-off. Spiked milfoil loves alkaline systems in which there are high concentrations of dissolved inorganic carbon.

Being able to distinguish between the North American and the spiked milfoils is important for environmental balancing reasons. One simple method to identify the difference is to take digital pictures and email them to The Weeders Digest or you could even put them in a ziplock bag and mail them to us with regular mail.

If you have specific questions and concerns, I suggest that you contact us at The Weeders Digest by visiting our website at or contact us at 877-224-4899

This article is written By Bruce Wahlstrom © copyright 2011 All rights reserved