From Dennis Patton:
When it comes to the lawn this growing season there have been very few complaints. The abundant rain has left most lawns a lush green, even this late into July without the need to water. That rarely happens in our typical summer climate.
But like most things in life a positive is often followed by a negative. This is the case of the above average rainfall and a pesky weed that has thrived during the wet, cool summer of 2015. It goes by several common names including nutsedge, nutgrass and water grass. The technical name is yellow nutsedge, which happens to be one of the most difficult lawn weeds to control.
Although this weed looks like a grass, it is really sedge, one of a group of plants that have triangular stems. As the name implies, yellow nutsedge is pale green to yellow in color. It grows rapidly in the spring and early summer, often sticking up above the rest of the lawn only a few days after mowing.
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Nutsedge grows best in moist lawns, often with poor drainage. The weed can also be introduced into better soil conditions through contaminated topsoil or nursery stock. As with many weeds, nutsedge is less competitive in a dense, healthy lawn than in a poorer, thinner turf. But with this summer’s weather it is popping up in places not seen before.
Pulling nutsedge is environmentally friendly but takes time
Nutsedge is difficult to control culturally because it produces numerous tubers that give rise to new plants. Pulling nutsedge will increase the number of plants because dormant tubers are activated. However, it is possible to control small stands of nutsedge by persistent pulling. Pulling will eventually weaken the plants and cause them to die out. Unfortunately most people give up or don’t pull often or long enough for this method to be highly effective.
Using herbicides to control nutsedge
Herbicide treatments are the best way of controlling this pesky weed. There are two common products on the market for control of nutsedge. They will have either active ingredients with Halosulfuron or Sulfentrazone. You will need to read the labels as these chemicals will not appear in the name easily seen on the container. If an infestation is not too severe, one application should take care of the problem. Usually it will take several applications and maybe a couple of years to clean up a heavy infestation, especially in wet years like this one. Be sure to read and follow all label instructions, as often it is recommended to apply when the nutsedge has reached the three-to-eight leaf stages for best results.
Since nutsedge is not a grassy or broadleaf weed, but sedge, many of the common broadleaf herbicides on the market will have little or no effect on its control. That is why it is important to search out these products specifically developed to control sedges. No matter what you call it, nutsedge, nutgrass or water grass, be sure to select the proper chemical and follow all label instructions for best control of this lawn weed problem.