How to Kill Spike Rush in a Lake

Inspect your lake or pond for the spike rush plant. Take pictures that you can cross-reference with the U.S. Department of Agriculture's illustrated Eleocharis guide (see Resources).

Pull every spike rush plant that you can from the roots. This is the most permanent solution to your problem. They could be along the shore on dry land or permanently in shallow water. Either way, try to get the roots, which cling to rhizomes under the surface. Continue to inspect the shoreline for young saplings and remove them as you find them.

Introduce a herd of goats to the area along the shore of the lake or pond. Texas A & M University Extension states that hand-pulling and goats are the only known biological fixes for the spike rush plant. Some farmers advertise the services of goats for lawn maintenance. Call you local agricultural extension office for help finding a local goat herder.

Employ a chemical herbicide only after checking with local health officials about its safe and legal usage. Texas A & M University, however, says several brands like Reward, Avast, Whitecap and Sonar contain the ingredients fluridone and diquat, which have proven effective for eradicating spike rush infestations. Estimate the area and volume of your pond or lake (see the second Resources section link for help), and follow the manufacturer's instructions specifically to add the right amount of herbicide.