Yellow nutsedge, or nutgrass, is a relatively common weed in lawns, landscapes and vegetable gardens. Although it looks like grass, it is actually a sedge.
Unlike grasses, sedges have triangular stems and the leaves are three-ranked instead of two-ranked. This means the blades come off the stems in three different directions not two.
Yellow nutsedge is pale green to yellow in color and grows rapidly in the spring and early summer. It is easy to identify because it grows taller than the rest of the lawn just a few days after mowing.
Normally found in wet areas, nutsedge is a good indicator of poor drainage or over watering. But it can be introduced into a well-drained site through contaminated topsoil or plants.
Nutsedge is difficult, if not impossible, to control with cultural practices because it produces numerous tubers that give rise to new plants. However, as with many weeds, nutsedge does not grow well in a dense, healthy lawn.
With this in mind, mow the grass higher than usual, fertilize at the appropriate times and water only when needed to keep your yard healthy.
By far, the best method of control is with the use of herbicides. There are few products labeled for use in the lawn, however. Manage is probably the safest and most effective product. It is expensive, but if an infestation is not too severe, one application should take care of the problem.
The Manage label states it should be applied after nutsedge has reached the three- to eight-leaf stage. Waiting until this growth stage apparently results in improved translocation of the active ingredient to the underground tubers and rhizomes.
MSMA (monosodium acid methanearsonate) can also be used, but is less effective than Manage and can cause temporary discoloration of the desirable turfgrass. MSMA is less expensive than Manage, and is more widely available in the homeowner market.
You can achieve fairly good control with repeat applications 10 to 14 days apart. MSMA is often sold under such generic names as "crabgrass killer" (because it is also used for postemergence crabgrass control) or "nutgrass killer." Of the two, Manage would be my first choice.
In the vegetable garden and flower beds, hand pulling and fresh mulch are probably the best options. Don't be afraid to pull small plants when they pop-up from time to time.
Contrary to what you sometimes hear, pulling the nutsedge by hand will not make the problem worse. You have to be persistent, but eventually the nutsedge will die out.
Around woody ornamentals, a directed spray at the weeds with Manage works well. But, do not spray the foliage, annual and perennial flowers, or the vegetable garden.
Yellow nutsedge, or waterweed, used to be a problem in my own landscape. However, with the use of herbicides, hand pulling and keeping the flower beds on the dry side, I have this weed pretty much under control.
From time to time, I will find that a new plant has sprung up, but I pull it, then replace the mulch and all is well.