Nutsedge Drives Homeowners Nuts!

May 13, 2016

Nutsedge Drives Homeowners Nuts!

As I was recently mowing my lawn AGAIN between rains, I noticed a few light yellow-green blades of grass that were even taller than the rest of my grass. This was in a protected area right next to a retaining wall so I think that is why this weed was a little earlier than I would normally expect. But it is a good reminder that yellow nutsedge is or soon will be showing up in lawns around Burt County. Once it does, it is the time to start controlling this pesky lawn weed.

Yellow nutsedge is a member of the sedge family although it closely resembles a grass. In fact it is frequently called nutgrass or watergrass. It is a common weed in lawns and landscapes, and can often be found in areas with moist soil. Yellow nutsedge is a perennial plant, meaning that the below ground portion of each plant survives the winter and generates new top growth each spring.

When closely examined, yellow nutsedge is found to have a very unique form and can easily be distinguished from turf grasses and other grassy weeds. The leaf blades are light yellowish-green and are "V" shaped with a prominent ridge down the center of the leaf blade. These leaves originate from the base of the plant which gives the lower stem a distinctive triangle shape.

The leaf blades always seem to grow faster than the surrounding grass, sticking up above the turf only a day or two after mowing. The root system is shallow and fibrous, often producing small nut-like tubers that serve as food storage organs. These small tubers will sprout and form new plants. The plants also spread by rhizomes, or root-like underground stems, which enables it to move rapidly throughout a lawn or landscape.

Controlling yellow nutsedge can be difficult. Pulling the weeds is effective IF you are willing to be persistent... especially if you start as soon as you see plants. You will kill new plants by pulling them before June 21. After June 21, or the longest day of the year, nutsedge will start to form tubers on new plants. However, if you pull a plant that is a year old or older, the small tubers have already formed and will sprout which can make it looks like the problem is as bad or worse than when you started.

But don't give up, these new plants can be controlled if you pull them within a week or two after emergence because they haven't formed new tubers yet. However, if new plants are allowed to mature and develop tubers before being pulled, then hand pulling will not provide adequate control.

In areas of heavy yellow nutsedge infestation, chemical control may provide the only viable option. Common grass and broadleaf herbicides will not control yellow nutsedge. Specialized herbicides for controlling sedges must be used. There are a couple effective herbicide currently available for yellow nutsedge control including Sedgehammer and Sedge Ender. Two or more application of herbicide will normally be needed to provide control.

If nutsedge is in a flowerbed, Sedgehammer (but NOT Sedge Ender) can be used to control it there. Your other option in a flower bed or among other ornamentals is to spot treat with a glyphosate-containing product like Roundup.  Carefully spray or use a paint brush to dab glyphosate on the nutsedge without getting it on your ornamentals will provide control.

When using any herbicide, carefully read and follow the label directions. When applying herbicides, avoid mowing about three days before treatment to be sure there is plenty of leaf surface area to adsorb the herbicide. Also, to ensure adequate herbicide absorption, do not water the lawn for at least 24 hours after you apply the herbicide.

Applications should be initiated as soon as you observe young, actively growing nutsedge plants. This is when it is most sensitive to herbicidal control and before nutlets have formed on the roots of new plants. Once this weed matures or nutlets have formed, control is more difficult regardless of the treatment schedule.

For more information on controlling yellow nutsedge, contact your local Nebraska Extension office.