Nutsedge Pre-emergent Weed Killer| Is It Effective?

Nutsedge (Cyperaceae) is a perennial weed that plagues pristine lawns all over the world. Surprisingly though, it’s neither a weed nor a grass. Being one of the most pestilent ‘weeds’ around, it’s in a separate category called a sedge. 

What makes it so prolific is the way it spreads. Unlike other weeds, its primary propagation method is underground tubers along with seed production. So, how do we combat this challenging turf invader? The best way is with an herbicide that will stamp it out from leaf to root and in my experience, the best way to do this is not through a nutsedge pre-emergent, but with a post-emergent herbicide instead. 

Choosing The Best Herbicide for Nutsedge 

Given its prolific spreading habits, nutsedge can be difficult to control. Pulling them out by hand with a weed puller is ok for very small patches but trying to dig up larger areas will only trigger other dormant tubers nearby. Plus, their spread can be so far-reaching, it is difficult to dig up all of the sedge plant. Instead, choosing the right herbicide can be a more effective way to control growth and spread without the work of removing them manually. 

Types Of Nutsedge 

With all the different weeds that make their way into our lawns, how do you identify nutsedge? There are two equally invasive varieties that have a slightly different appearance. Let’s take a look at each and the tell-tale signs of an infestation. 

Purple Nutsedge 

Purple nutsedge is recognizable by its purplish seed pods that rise from light green clumps. They’ll be lighter and grow much higher than standard turf, making them easy to spot. Purple nutsedge also spreads in chains of tubers, rather than individually. Making them more difficult to eradicate by hand. 

Yellow Nutsedge 

Yellow nutsedge has a similar appearance and growth habit. But with seed pods that bloom in a dark golden color. This variety reproduces by the development of individual tubers rather than chains.

Why is Nutsedge Hard to Kill? 

Nutsedge is hard to eliminate simply because it reproduces faster than we can remove it. Also, tubers will replicate themselves in winter when the soil is often too hard to dig through. That’s why it’s important to find a nutsedge herbicide that can eradicate the entire weed and not just tackle pre-germinated seeds as a nutsedge pre-emergent would. 

How do you kill nutsedge without killing grass? 

The best weed-killing herbicide will, of course, be one that doesn’t kill your lawn in the process. So, what does that look like? For border plantings, you can gently spray or brush a general herbicide onto individual nutsedge shoots. But to protect lawns, you’ll want to consider a “selective” herbicide that’s formulated to focus on the unique biology of weeds. Leaving your lawn intact.  

When choosing a herbicide to rid your lawn of nutsedge, you’ll need to know what type of turf you have. Some herbicides are not suitable for all types of grass so have a good read of the label before you commit to a purchase.

Does Pre-Emergent Stop Nutsedge? 

When I’m tackling nutsedge I find that pre-emergents can have little or no effectiveness even if applied to nutsedge seeds that are yet to germinate. This is because of dormant tubers that lurk beneath the soil which are simply not affected by the active ingredients in pre-emergent herbicides. That’s why I always opt for a post-emergent for dealing with nutsedge.

I’ve found that attacking nutsedge during the active growing season – roots and all – with a good quality post-emergent is a far more effective method of banishing this pesky sedge for good. Post emergents are typically sprayed onto the leaves and stems of growing weeds. The herbicide chemicals become systematically absorbed into the entire system of the weed until it reaches the root. Once the root has absorbed the chemical it really is game over.


Nutsedge Herbicide Reviews 

While there are no specific nutsedge pre-emergent products on the market, there are quite a few herbicides that will serve a similar function, when used as directed. All of which I’ve personally tested to see which was most effective.

To save you the time and expense of doing your own testing, I offer the following 4 nutsedge weed killer options that I’ve found to work the best. 


1. Ortho Nutsedge Killer for Lawns Spray Bottle

Ortho | Nutsedge Killer for Lawns

I’ll start with Ortho’s nutsedge killer. The ease of use with this can’t be beaten. Just attach it to your hose and spray evenly on newly emerged and established weeds either as a spot treatment or for your entire lawn. Sulfentrazone is the active ingredient in this selective herbicide meaning it will kill weeds and not your lawn and has been shown to be an effective weedkiller for over 50 varieties of sedge and broadleaf.

I do advise you to read the label thoroughly and look out for the list of protected ornamentals before spraying this in your garden or veg beds.  The labeling is clear and concise and makes identifying whether it’s right for your garden a breeze.

This one quart-sized container will see you good for 5,000 sq. ft and you get a comprehensive list of all the southern and northern turf grasses that it can be used on included Zoysia Grass, St. Augustine, and Bermuda.

Expect to see discolored and brown-looking nutsedge after just a few days. And in a few weeks, you won’t be able to see any visible traces of those annoying weeds growing above the surface of your lawn. It’s rainproof too, which is another bonus and avoids the need for reapplication so soon after the first. Definitely my preferred product, you can check the latest price for Ortho’s Nutsedge killer here.

How To Use: Shake well. Then, attach to your garden hose and spray evenly over your lawn. This bottle will cover an area of up to 5000 sq ft. You’ll need to wait until the product has dried before allowing pets and children onto the areas that you’ve treated.

Customer Reviews:  Consumers agree that the speed at which Ortho’s Nutsedge Killer works is outstanding. Very good value for money. Research on use for your particular type of lawn is recommended. 4.4 out of 5 stars

Pros      

  • Results in just a few days
  • Very simple to use
  • One bottle covers up to 5000 sq ft

Cons


2. SedgeHammer Nutsedge Selective Weed Killer Herbicide  

SedgeHammer | Nutsedge Selective Weed Killer 

Next up is this water-soluble, selective herbicide offering from SedgeHammer. This one works by specifically targeting the acetolactate enzyme that is unique to sedge weeds. It firstly penetrates the outer areas of the sedge and quickly travels throughout the entire system, ultimately halting growth in both tubers and shoots, and thus killing the offending weed.

This one took a little more effort to assemble and you’ll need a handheld or backpack sprayer to apply. It’s also worth noting that this one is not really suitable as a spot treatment as once it has been diluted it needs to be used up and can’t be left hanging around.

The trick with this one is to apply on dry grass ideally where there has been no rainfall and just after the morning dew has cleared. You also need to avoid spraying in the heat of the day as this will affect the effectiveness of the herbicide. But if it is nutsedge in particular that needs getting gone, then it’s well worth investing in the time to read the instructions thoroughly because you can expect to see great results and little or no return of the weed.

When I tested this I began to see results after about 2 weeks when brown rings began to appear around the nutsedge. It took nearly a full month to see the finished results and banished nutsedge. But, time, patience, and care equal long-term success. Click here for SedgeHammer from Amazon.com

How To Use: Mix granules with one gallon of water and spray nutsedge weeds thoroughly. The diluted solution will cover approximately 1200 sq. ft.

Customer Reviews: Lawn connoisseurs seem to be impressed with the duration of effectiveness using such a small amount. Repeat applications may be necessary for stubborn tubers but well worth the effort. This is a great option if nutsedge is the main problem as the list of weeds that it effectively treats is significantly less than with Ortho. 4.4 out of 5 stars.

Pros      

  • Kills nutsedge and keep it at bay for longer
  • Works especially well in tandem with Burmudagrass Turf

Cons

  • More than one packet may be needed for larger infestations

3. Bonide Sedge Ender and Weed Killer 

Bonide Sedge Ender and Weed Killer 

I found this water-soluble concentrate from Bonide to work the best on stubborn purple nutsedge. If you kill a couple of tubers, the rest of the chain will just grow more. But, this spreads from one tuber to all the others.

I applied this with a hand-sprayer and was pleasantly surprised to see browning after just 2 days. I applied it in mid-summer when nutsedge was in the middle of its active growing season for quick metabolizing. After 5 days, the weeds I sprayed were crispy and done. Click here for Bonide Sedge Ender and Weed Killer.

How To Use: Mix the recommended amount for your grass-type with 4 liters (1 gallon) of water for every 1000 sq ft of application area.

Customer Reviews: For severe infestations, consumers all over the lawn care spectrum are recommending Sedge Ender. When used as directed, you’ll enjoy fast, long-term results without the expense of constant re-applications.  4.4 out of 5 stars

Pros      

  • Signs of effectiveness in 48 hours
  • Long term results

Cons

  • Not as effective when incorrect amount is used

4. Ferti-lome Weed-Out Nutsedge Control Concentrate 

Ferti-lome Weed-Out Nutsedge Control Concentrate

This option requires a quick google search to see if it’s appropriate for your type of grass. I really liked this one because it worked fast. Even when using it 3 hours before a heavy rainfall. I tested this on both types of nutsedge. And it rapidly spread into every root, tuber, shoot, and seed plume. 

It did take a little longer to see results (2 weeks) but I thought it was worth the broad range of coverage. Both purple and yellow nutsedge as well as a few other stragglers, here and there. Check prices for Fertilome Weed Out here at Amazon.com

How To Use: Mix 1.25 oz with 4 liters (1 gallon) of water in either a hand trigger or pump sprayer for every 1000 sq ft. of the target area.

Customer Reviews:  Per consumer feedback, this product kills nutsedge through the leaves, not the tubers. So, it may take a few applications to finish the job. But, when it’s done, it’s done. 4.8 out of 5 stars. The highest on my list of picks. 

Pros      

  • Easy application method
  • Broad range of weed type coverage

Cons

  • May show yellowing when used with certain types of lawn turf

When To Apply Herbicide For Nutsedge 

The most effective time to apply a nutsedge herbicide is in late spring or early summer when this invasive plant is in its active growing stage. During this time, the herbicide will be better absorbed and metabolized by the roots, tubers, stems, and leaves. 

When Does Nutsedge Germinate? 

Nutsedge typically germinates from tubers in early spring, just as its active growing season begins. Once this occurs, an herbicide can then be applied that will spread throughout the plant for elimination.  Depending on the severity of tuber infestation, more than one application may be necessary. 

How to Apply Weed Killer For Nutsedge 

Most herbicides appropriate for nutsedge will come in liquid form. Either pre-mixed or water-soluble. These can easily be applied by attaching the pre-mixed bottle to your hose. Or combining water-soluble options in a backpack or hand sprayer. 

Post-emergent herbicides do this job best as they are intended to penetrate the roots and stems and over time the herbicide gets absorbed throughout the remainder of the plant, eventually reaching the roots.

Verdict: Nutsedge Weed Killer 

After all my testing, my final verdict is this. Nutsedge can be tricky to eliminate because of its intensely invasive nature. Especially when factoring in the severity of the infestation and what type of grass you have.

So, for treating nutsedge as well as a variety of other weeds in most types of southern and northern lawns, I recommend Orthos Nutsedge Killer. It’s suitable for spot treating and covering large areas and it’s ready to use.

On the other hand, if Nutsedge is your main problem, then I recommend SedgeHammer. A water-soluble option that is great for treating large areas of even the most aggressive forms of nutsedge. Alternatively, if stubborn purple nutsedge is wreaking havoc on your lawn, I recommend Bonide concentrate.

Like most things, with just a little patience and know-how, it is possible to achieve a lawn that will be the envy of all your neighbors and friends. I hope the results of my research will provide you with all you need for your own success. 

Nutsedge Pre-Emergent | Is It Effective? FAQ’s