A frequently asked question about yellow nutsedge is "What is this grass
weed?" Well, it looks like a grass but is really a sedge and it's on my
list of 10 Most Unwanted Weeds. Nutsedge spreads and grows
rapidly in lawns, gardens and landscape beds and takes a stubborn
determination to control once established.
Yellow nutsedge can be found in yards from Maine to California, it is a weed in both cool-season and warm-season lawns and most commonly a problem in wet or damp areas.
Yellow Nutsedge Cyperus esculentus (often called "Nutgrass") gets its name from its yellow/brown seedheads and the tubers or nutlets that form at the tips of the rhizomes (spreading underground stems). The triangular stems grow upright and have glossy leaves that are a light green or yellow-green color and have a very distinct mid-rib. It looks ugly in lawns because it grows faster than grass and really sticks out...disrupting the uniform appearance of a groomed lawn.
What to look for:
Sedges love moist areas and sites that stay wet from excessive
irrigation or poor drainage are likely to become infested with
In late June and into July, the nutlets start to form on the tips
of the rhizomes. It is important to work on weed control before the
nutlets form because several new plants can grow from a single nutlet
and they remain in the soil several years.
It can take several years to get rid of this weed, new plants are continuously produced from the nutlets left in the soil. Timing and persistence are the keys to winning the battle against nutsedge, weed control is always most effective on young, actively growing plants. Whether hand weeding or using a chemical control, it is important to get after young plants before they produce nutlets or go to seed--this will reduce the numbers of new plants.
Nutsedge is easy to hand weed however, it should be pulled when plants are young and then continue to scout the area to remove new plants as they appear.
Chemical control options include non-selective and selective herbicides. Make sure the herbicide either contains a non-ionic surfactant or be sure to add one to the tank mix. The surfactant will make herbicide applications work better by helping the chemical stick to the glossy, waxy leaves and penetrate into the plant.
Glyphosate (Roundup) is an effective non-selective herbicide that can be used on nutgrass in landscape beds. Glyphosate takes about a week to work and follow-up applications in two or three weeks are usually required.
Here's a helpful video from University of Nebraska Extension: