How to Use SedgeHammer+ to Control Nutsedge

As we enter into the warmer months, it’s not uncommon to start seeing pesky weeds pop up in our lawns and gardens. One of the infamously hard-to-control weeds is known as nutsedge and there are several variations of this weed. Yellow nutsedge and purple nutsedge are the most common in the United States—and both can quickly turn into monsters for your yard. Unfortunately, this weed will continue growing all summer long and until the first freeze of winter.

Unlike other common lawn weeds, nutsedge does not fall into the grassy or broadleaf weed category but is instead a class of its own. Although similar in appearance to a grass, it can be differentiated by its shiny yellow-green color and V-shaped stem that will feel triangular in your hand when it is rolled between your fingers. The yellow nutsedge has yellow seedheads while purple nutsedge has purple seed heads.

Found throughout the United States, it is quite common to see nutsedge in moist areas of the lawn that are poorly drained, especially during periods of hot weather. This Sod University article discusses the characteristics of nutsedge and highlights the weed control product SedgeHammer+, one of the most renown products that controls this obnoxious weed. First, let’s discuss nutsedge and its characteristics. 

Nutsedge Characteristics and Traits 

Nutsedge can be seen for the majority of the year, but is typically most active and noticeable during the summer when it grows faster and taller than the turfgrass it is invading. Normally, the plant emerges towards the end of April and into the beginning of May and will continue to grow until a frost hits. However, nutsedge is commonly spotted during the early spring In southern parts of the United States.

Since yellow and purple nutsedge are perennial weeds, the above-ground tissue will die in the cold while the below ground portion will survive in the soil and germinate the following season.

Sadly for us homeowners, nutsedge plants produce underground tubers that look like nuts (hints its name). The underground tubers can remain even when the plant is pulled out of the soil, resulting in the germination of more plants. In fact, one nutsedge plant alone can produce hundreds of tubers when it is actively growing.

Pictured above from left to right: Yellow nutsedge and purple nutsedge.

Nutsedge is often recognized by its spiky seed heads represented in the yellow and purple nutsedge images above. In a well maintained lawn, however, nutsedge becomes hard to recognize with frequent mowing because the weed doesn’t get the opportunity to sprout identifiable seed heads.

The images below give a visual representation of what the nutsedge plant looks like before it sprouts seed heads. This is usually how most homeowners will see nutsedge growing in their lawn if the weed is present.

Pictured above: Images of sedge before sprouting seed heads.

Non-Chemical Control of Nutsedge

To begin controlling nutsedge, start by identifying cultural problems in your lawn including overwatering and thinning turfgrass. A healthy lawn can choke out weeds and resist other environmental stressors. The most important step that can be taken in controlling this weed maintaining a lawn that is dense, healthy, irrigated and fertilized on a proper schedule. Refer to our care guides for more information for your specific turfgrass.

Some tried and true methods of control include keeping your lawn fertilized with Lawnifi®, which provides the grass with the nutrients it needs to stay dense and healthy so that it can keep nutsedge away. A strong, dense lawn will outcompete weeds.

Nutsedge thrives in areas of turfgrass that have moist soil, are mown too short or have a thin canopy. Therefore, ensuring that your irrigation system is correct and raising your mowing height will help your lawn outcompete potential sedge problems.

Hand-weeding is also an option if the problem is detected early; however, because of its extensive tuber system, it is essential to be thorough when removing the weed. To do so, digging around the base of the nutsedge may be necessary to loosen the soil and remove its below ground system. It is also important to check the area frequently after weeding in case additional plants develop afterwards.

How to Control Nutsedge with SedgeHammer+

Chemical control is also an option if the problem cannot be controlled by cultural practices or hand-weeding. One of the most effective post-emergent control options is SedgeHammer+ (active ingredient Halosulfuron-methyl), which can be mixed with water and spread evenly over the grass and weeds.

A post-emergent herbicide controls currently existing weeds while a pre-emergent, as its name suggests, prevents weeds.

SedgeHammer+ works best when applied in the spring and when the nutsedge plants have between 3–8 leaves or produces tubers. As a selective herbicide, SedgeHammer+ offers control over both yellow and purple nutsedge, kyllinga and other listed broadleaf weeds listed on the product label below.

A selective herbicide only controls the weeds listed on its label whereas a non-selective herbicide, like glyphosate, kills all vegetation it comes into contact with—including your lawn.

SedgeHammer+ is a systemic, post-emergent herbicide meaning that it works best when applied on nutsedge after it has emerged from the soil’s surface and works systemically through the plant’s system to kill it. The chemicals move through the plant’s system slowly so that it can effectively reach the whole plant and roots as much as possible.

Sedgehammer+ can take somewhere between 3–5 weeks to kill down to the root and can be reapplied after six weeks if a second application is needed.

One final post-emergent, Mesotrione 4SC Select (active ingredient Mesotrione), can control some nutsedge in combination with other grassy weeds and may be a good option if multiple weeds are occurring in your lawn. However, Mesotrione 4SC Select is only labeled to control yellow nutsedge, not purple nutsedge or kyllinga.

SedgeHammer+ Product Label

How to Use SedgeHammer+

A single packet of SedgeHammer+ covers 1,000 sq. ft. in your yard. Apply SedgeHammer+ for post-emergence control of purple or yellow nutsedge, kyllinga and broadleaf weeds. Mix 0.5 oz. (13.5 grams) of this product (one pouch) in one gallon of water to treat 1,000 sq. ft. of turfgrass. Mix or shake the solution to ensure ingredients are completely dispersed. Spray the target weeds thoroughly and wet the entire leaf surface of the undesirable plants. For best results, spray nutsedge after it has reached the 3–8 leaf stage of growth.

Tolerant Turfgrass

SedgeHammer+ can be safely used on a variety of cool and warm season turfgrasses including the following: creeping bentgrass, fine fescue, perennial ryegrass, Kentucky Bluegrass, tall fescue, bahiagrass, bermuda grass, buffalograss, centipede grass, seashore paspalum, St. Augustine grass, kikuyugrass and zoysia grass.

Before attempting to treat sedge with chemicals, it is important to read the product label carefully to ensure that it will be compatible with your turf and not cause any damage. Refer to the product label above for a full list of application and mixing instructions.

Be sure to check out the rest of our herbicide products online here. For more information on weed control fundamentals, check out our Weed Control and Identifying Common Lawn Weeds blogs.