I'll bet you've seen Cyperus esculentus growing in your lawn, or perhaps a neighbor’s, and didn't even know it. Commonly known as yellow nutsedge, most folks think it's an odd type of grass that grows much faster than the rest. On an otherwise nice, thick and uniform lawn, its characteristic yellow-green blade stands out like acne on a supermodel.
Signs You May Have Yellow Nutsedge
How do you know if your lawn has it? If two to three days after you mow, you notice certain spots already growing up faster than the rest of the lawn … it's likely. If you reach down and give it a tug and the plant pulls out easily … it's even more probable. If all the above is present, and the grass-like blades have a deep 'V' cross-section with a triangular stem … it's definite. You sir, have nutsedge in your lawn.
Since the record rainfall our region experienced in late 2018 and early 2019, I've seen more yellow nutsedge in NOVA then I have in 35+ years. Nutsedge loves poorly drained soils. Its natural habitat is around the edge of a pond. While it will usually start in a poorly drained area of your lawn, nutsedge can adapt and spread throughout your lawn. To minimize this do not let it go to seed! If allowed to grow tall enough, it will get a spiky seed head that can produce up to 2,400 seeds per plant. In addition, don't be fooled by how easily it pulls out of the ground. I guarantee you ain't getting all of it. The plant gets its name from many small nut-like tubers growing several inches down and without removing all the roots, it will simply grow back, quick and thick.
If you procrastinate long enough, the yellow nutsedge will seemingly go away on its own. As the weather cools in early fall, the leaves will die back. Unfortunately, we're not that lucky. It is an annoying perennial so when the soil warms enough late May/June the following year, the yellow nutsedge will return. It will continue to spread and come back every year until you do something about it.
Time to Embrace a Chemical Treatment Plan
Since pulling it out is not an option, you will need to embrace a chemical treatment plan that will selectively kill the yellow nutsedge without harming the good grasses. Applying treatments at select times will ensure the highest rate of success... To truly eradicate the yellow nutsedge, you’ll need a two-year control plan even under the best of circumstances. Within the first three to four weeks of it leafing out you need to treat. If it has not completely died back in 21 days, treat again. Hopefully, you won't see it again that year but it will almost certainly come back the following year. Rinse and repeat in year two. With any luck … problem solved (although some may want to say a few hopeful words along the way).
Not sure what to use to control the yellow nutsedge? As the chief agronomist at Bio Green Outdoor Services, I’ve searched for the best solution for a long time. There are many herbicides labeled for selective control of nutsedge and I've tried most of them over the years with limited success. That is until recently when, on the advice of my materials vendor, I started using Dismiss NXT. This stuff is the “juice” and I strongly recommend it. Dismiss NXT also works on yellow nutsedge's nasty cousin, Kyllinga, but that discussion is for another day.
Image by: Homer Edward Price, Own Work, CC BY-SA 4.0, https://upload.wikimedia.org/wikipedia/commons/4/4f/Yellow_Nutsedge_Cyperus_esculentus_%2843998391481%29.jpg