Click for a hub of Extension resources related to the current COVID-19 situation.
COVID-19 Resources

Spike Rush

Eleocharis spp.

Management Options

Mechanical/Physical Control Options

Spike rushes can be cut and the rhizomes can be dug up but physical control is difficult because it can reestablish from seeds or remaining rhizomes.

Biological Control Options

There is no known biological control for spike rushes, although goats are known to forage on many types of emergent vegetation.

Chemical Control Options

The active ingredients that have been successful in treating spike rushes include diquat (G) and fluridone (G). E = excellent, G = good

Reward is a liquid diquat formulation that has been effective on spike rushes. 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.

Sonar,  Avast , and  Whitecap are floridone compounds and comes in both liquid and granular formulations, and have been effective on spike rushes. 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.

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 (See General Water Use Restrictions).

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.

Cultivation Options

Spike rushes can be propagated by transplanting whole plants with rhizomes into shallow water areas during the winter or early spring.