Monthly Archives: June 2010

What is Milfoil?

Northern Milfoil vs Eurasian Milfoil (Good vs Evil)Eurasian Water Milfoil has reputation for permanently destroying a lake or a pond and oftentimes crushes the dreams of waterfront living.

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 2010 All rights reserved

What is Water Milfoil

Eurasian watermilfoil was accidently introduced to North America from Europe. Spread westward into inland lakes primarily by boats and also by waterbirds, it reached Midwestern states between the 1950s and 1980s.
In nutrient-rich lakes it can form thick underwater stands of tangled stems and vast mats of vegetation at the water’s surface. In shallow areas the plant can interfere with water recreation such as boating, fishing, and swimming. The plant’s floating canopy can also crowd out important native water plants.
A key factor in the plant’s success is its ability to reproduce through stem fragmentation and runners. A single segment of stem and leaves can take root and form a new colony. Fragments clinging to boats and trailers can spread the plant from lake to lake. The mechanical clearing of aquatic plants for beaches, docks, and landings creates thousands of new stem fragments. Removing native vegetation creates perfect habitat for invading Eurasian watermilfoil.

Likely means of spread: Milfoil may become entangled in boat propellers, or may attach to keels and rudders of sailboat. Stems can become lodged among any watercraft apparatus or sports equipment that moves through the water, especially boat trailers.Eurasian watermilfoil has difficulty becoming established in lakes with well established populations of native plants. In some lakes the plant appears to coexist with native flora and has little impact on fish and other aquatic animals.  For more information visit

What is Eurasian Water Milfoil

Myriophyllum (water milfoil) is a genus of about 45 species of freshwater aquatic plants, with acosmopolitan distribution. Its name comes from Latin, “myrio” meaning “too many to count”, and “phyllum”, meaning “leaf”.

These submersed aquatic plants have whorled leaves that are finely, pinnately divided. The leaves above the water are stiffer and smaller than the submerged leaves on the same plant. The flowersare small with four petals and are borne in the leaf axils or in a terminal, emergent spike.

Waterfowl eat the fruits and leaves and muskrats eat the entire plant.

It has a long soft but fairly brittle stem. The leaves of the plant only present near surface of the water, while flowers are formed above the surface of the pond.

Various species of water milfoil have become naturalized in water bodies of nearly every state in the continental U.S.

This plant may be a hidden resource, eventually seen as a valuable cellulose feed stock in abiofuel refinery. Cellulosic ethanol, or butanol fuel are seen by many as growing trends in green fuels (including jet fuel).

A common species, Eurasian water milfoil, is often controlled with herbicide containing the chemical diquat dibromide. Control can also be done through careful mechanical management, such as with WeedShear but caution must be used since this is a fragmenting plant, and the fragments may grow back. Milfoil is an invasive aquatic plant species from Asia.

Mechanical management can include the use of a long reach lake rake or aquatic weed razor blade tool. Using these tools would be similar to lawn work. These tools are most effective before seeds set. Another very effective use is to keep the plants from ever starting to grow through the use of a Weed Roller or a Beach Groomer. These are considered to be automated and unattended machines. Permits may be required by various states. A guide to state permits and aquatic vegetation management can be found at