These submersed aquatic plants are perhaps most commonly recognized for having elongate stems with air canals and whorled leaves that are finely, pinnately divided, but there are many exceptions. For example, the North American species M. tenellum has alternately arranged scale like leaves, while many Australian species have small alternate or opposite leaves that lack dissection. The plants are usually heterophyllous, leaves above the water are often stiffer and smaller than the submerged leaves on the same plant and can lack dissection. Plants are monoecious or dioecious, the flowers are small, 4(2)-parted and usually borne in emergent leaf axils. The 'female' flowers usually lack petals. The fruit is a schizocarp that splits into four (two) nutlets at maturity.
The fruits and leaves can be an important food source for waterfowl, which are thought to be an important source of seed and clonal dispersal.
Herbicide Management Options:
Sonar: Is a florid one compound and comes in a liquid formulation, and have been effective on Water Milfoil. This is a broad spectrum, systemic herbicide. Systemic herbicides are absorbed and move within the plant to the site of action. Systemic herbicides tend to act more slowly than contact herbicides.
Reward: is a liquid diquat formulation that has been effective on Millfoil. It is a contact herbicide. Contact herbicides act quickly and kill all plants cells that they contact. A non-ionic aquatically registered surfactant (see the label) will have to be added to the Reward solution for good results.
Biological Management Options:
Grass Carp: will consume Water Milfoil, but Water Milfoil is not a preferred food item. Grass carp stocking rates to control Water Milfoil are 20 fish per surface acre of plant biomass. In South Carolina, only Triploid Grass Carp are legal and a permit from the South Carolina Department of Natural Resources is required. AMS is licensed to provide these permits for you.