Waterstargrass

Control Options

Cultivation Options

Description of This Plant

Control Options

Mechanical/Physical

Water stargrass can be removed by raking or seining it from the pond but will reestablish from any remaining roots.

Fertilization to produce a phytoplankton or algal "bloom" prevents the establishment of most bottom rooted aquatic weeds and produces a strong food chain to the pond fish.

Non-toxic dyes or colorants prevent or reduce aquatic plant growth by limiting sunlight penetration, similar to fertilization. Aquashade is an example of non-toxic dye and other products are available. However, dyes do not enhance the natural food chain and may suppress the natural food chain of the pond.

Biological

Grass carp will seldom control aquatic vegetation the first year they are stocked. They will consume water stargrass. Grass carp stocking rates to control water stargrass are usually in the range of 7 to 15 per surface acre. In Texas, only triploid grass carp are legal and a permit from the Texas Parks and Wildlife Department is required before they can be purchased from a certified dealer.

Chemical

The active ingredients that have been successful in treating water stargrass include the endothall (E) and fluridone (E) where it is submerged and glyphosate (G) where it is emergent. E = excellent, G = good

Aquathol, Aquathol K, and Aquathol Super K are dipotassium salts of endothall and comes in both liquid and granular formulations. These endothall products have been effective on water stargrass. Contact herbicides act quickly and kill all plants cells that they contact.

Sonar and Avast are fluridone compounds, come in both liquid and granular formulations, and have been effective on submerged water stargrass. These are 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.

Rodeo, Aquamaster, Eraser AQ, Touchdown Pro, and AquaNeatare liquid glyphosate formulations and have been effective on water stargrass that is on moist soils, out of the water. These are broad spectrum, systemic herbicides. Systemic herbicides are absorbed and move within the plant to the site of action. Systemic herbicides tend to act more slowly than contact herbicides. An aquatically registered surfactant (see the label) will have to be added to the glyphosate solution for good results.

One danger with any chemical control method is the chance of an oxygen depletion after the treatment caused by the decomposition of the dead plant material. Oxygen depletions can kill fish in the pond. If the pond is heavily infested with weeds it may be possible (depending on the herbicide chosen) to treat the pond in sections and let each section decompose for about two weeks before treating another section. Aeration, particularly at night, for several days after treatment may help control the oxygen depletion.

One common problem in using aquatic herbicides is determining area and/or volume of the pond or area to be treated. To assist you with these determinations see SRAC #103 Calculating Area and Volume of Ponds and Tanks.

Many aquatically registered herbicides have water use restrictions. For General Water Use Restrictions click here.

To see the labels for these products click on the name. Always read and follow all label directions. Check label for specific water use restrictions.