Tuberous rhizomes are a type of weed with a stalk underground like a root, the rhizome, and an above ground bulb, the tuber. The tuberous rhizome weeds, such as nutsedge, the Jerusalem artichoke or quackgrass, are an aggressive type of weed. They take root and then take over a lawn or garden. They are also perennial weeds, meaning they die in the winter only to come back the next spring. Killing the tuberous rhizome weeds is the only way to get rid of them.
Spray the weeds with a glyphosate weed killing chemical. According to the University of Minnesota, spray a glyphosate weed killer on the plants when the forecast does not call for rain for more than 48 hours and wind is minimal. The chemical will kill the weeds. For tuberous rhizome weeds in perennial flowerbeds, such as daylilies, the University suggests using a small paintbrush and applying the chemical to the leaves of the weed to avoid accidentally killing your flowers.
Put down nitrogen fertilisers. The University of Minnesota states that the application of nitrogen fertilisers combined with the glyphosate will cause the plant to move the poison around and kill off the entire plant.
Dig the rhizomes out of the soil. Clemson University suggests digging at least 10-inches deep and 8 to 10 inches around the leaves of the plant before the tubers have a chance to develop to remove the entire plant. This is only effective if the plants have not yet spread and the patches of tuberous rhizome weeds are still small patches.
Cover the garden with mulch or put in cover plants. These two options will smother the tuberous rhizomes and make conditions too dry for the plant to take root. It is useful in both preventive and later controlling methods.
Never break up the weed by tilling. It will end up rapidly multiplying if broken up.