What's in this guide
What Is Nutsedge?
Nutsedge — also called nut grass or water grass — is one of the most frustrating weeds a homeowner can face. Unlike most lawn weeds, nutsedge is a sedge, not a true grass. That distinction matters a lot: most standard lawn herbicides slide right off it without doing a thing.
It thrives in warm, wet conditions and spreads aggressively through underground tubers called nutlets. For every visible plant you pull, there can be up to 18 nutlets buried in the soil, each capable of sprouting a new plant the following season. Pulling it by hand actually makes things worse — disturbing the soil spreads the nutlets further.
There are two main species to know: yellow nutsedge (Cyperus esculentus), the most common in North American lawns, and purple nutsedge (Cyperus rotundus), which is more aggressive and harder to control. Both can overtake a lawn within a single growing season if left untreated.
How to Identify Nutsedge in Your Lawn
Nutsedge is often mistaken for crabgrass or tall fescue. Here's the fastest way to tell them apart:
- Triangle stem: Roll the stem between your fingers — nutsedge has a distinctly triangular, three-sided stem. Grasses are round or flat.
- Bright yellow-green color: It's noticeably lighter and yellower than most lawn grasses, even from a distance.
- Faster growth: After mowing, nutsedge grows back within days and stands above the rest of the lawn.
- Leaves in groups of three: Nutsedge leaves emerge from the base in sets of three (the "sedge triangle rule").
- Waxy texture: Leaves feel slightly glossy or waxy compared to regular grass blades.
Hand-pulling nutsedge breaks the tuber chain underground, spreading nutlets further into your lawn. Always use a selective herbicide for proper control.
🔍 Is It Nutsedge? — Quick ID Checker
Answer 4 quick questions about the weed in your lawn and we'll tell you if it's likely nutsedge — and which killer to use.
Q1 — What shape is the stem when you roll it between your fingers?
1. Sedgehammer Plus Weed Killer
Sedgehammer Plus (by Gowan Company) is the gold standard for nutsedge control in residential lawns. Its active ingredient, halosulfuron-methyl, works by disrupting the amino acid synthesis in sedge plants — killing them all the way down to the tuber, not just burning the top growth.
It's highly selective, meaning it won't harm common turfgrasses including Kentucky bluegrass, fescues, bermudagrass, and St. Augustine when applied correctly. The "Plus" version includes a built-in surfactant, so you don't need to buy a separate wetting agent. Apply when nutsedge is actively growing, typically late spring through early summer.
You'll notice yellowing and browning of the nutsedge leaves within 7–10 days. Full kill down to the nutlets takes 2–3 weeks. A second application 6–8 weeks later is recommended for heavy infestations to catch any new growth from surviving nutlets.
Pros
- Controls both yellow and purple nutsedge
- Kills down to the tubers — prevents regrowth
- Safe on most common lawn grasses
- Built-in surfactant — fewer products to buy
- Works on 30+ other weed species too
Cons
- Requires mixing — not a ready-to-use spray
- Results take 2–3 weeks to fully appear
- May need a second application for heavy patches
2. Tenacity Herbicide (Mesotrione)
Tenacity is a versatile herbicide from Syngenta that stands out because it works both pre-emergence and post-emergence — meaning you can use it before weeds germinate in spring, or on weeds already actively growing. Its active ingredient, mesotrione, works by blocking carotenoid biosynthesis, which causes the plant to bleach white before dying. This white-bleaching effect is normal and expected.
For nutsedge, Tenacity is most effective against yellow nutsedge. It provides good suppression but may require 2–3 applications spaced 2–3 weeks apart for full control. Because Tenacity doesn't include a surfactant, you need to add one (like NIS or methylated seed oil) at the labeled rate for best results. Without it, the product will bead off the waxy nutsedge leaves.
It's approved for use on many cool-season and warm-season grasses and doubles as a broadleaf weed and crabgrass killer — making it extremely useful if you're dealing with multiple weed types at once.
Pros
- Pre & post-emergence — very versatile
- Controls 46+ weed species including crabgrass and dandelion
- Safe on most cool & warm-season grasses
- Can be used at lawn seeding time (unique)
Cons
- Requires separate surfactant — adds cost
- White bleaching on lawn is alarming (but temporary)
- Multiple applications needed for nutsedge
3. Certainty Herbicide (Sulfosulfuron)
Certainty is a professional-grade herbicide manufactured by Bayer that uses sulfosulfuron as its active ingredient. It's primarily a warm-season grass product, meaning it's best suited for lawns with bermudagrass, zoysiagrass, and St. Augustine — and should be avoided on cool-season grasses like fescue or bluegrass, where it can cause injury.
Certainty is a great choice if you have a warm-season lawn with both nutsedge and stubborn broadleaf weeds like clover, ground ivy, dandelion, chickweed, and thistle. It controls a wide spectrum in a single pass. For nutsedge specifically, apply when plants are actively growing and less than 6 inches tall for best uptake. Results appear within 1–2 weeks.
Certainty is NOT safe on cool-season grasses (Kentucky bluegrass, tall fescue, perennial ryegrass). Use Sedgehammer or Tenacity if your lawn has cool-season grasses.
Pros
- Controls nutsedge and broadleaf weeds in one application
- Professional strength — fast visible results
- Works on warm-season grasses without damage
Cons
- NOT safe on cool-season grasses — can injure lawn
- Requires mixing and a surfactant
- Higher cost vs. consumer products
Ortho Nutsedge Killer is a fast-acting ready-to-use formula for smaller patches — no mixing needed.
4. Ortho Nutsedge Killer
Ortho Nutsedge Killer is the most accessible option on this list. It's a ready-to-spray concentrate designed for homeowners who want fast, no-fuss nutsedge control without measuring or mixing. Its active ingredient, sulfentrazone, disrupts porphyrin synthesis in the weed, causing cell membrane breakdown and rapid death.
It works on both cool-season and warm-season grasses and is safe for most residential turf types including fescues, ryegrass, bermudagrass, and zoysia. In addition to nutsedge, it also knocks out spurge, chickweed, clover, and a handful of other common weeds. For best results, apply when weeds are actively growing and less than 3 inches tall. Repeat in 4–6 weeks if regrowth appears.
It's widely available at Home Depot, Walmart, and most garden centers — making it the easiest option to grab the same day you spot nutsedge in your lawn.
Pros
- Ready-to-use concentrate — no mixing needed
- Available at big box stores same day
- Safe on both cool & warm-season grasses
- Also kills spurge, clover, chickweed
Cons
- Slower results vs. halosulfuron products
- Less effective against purple nutsedge
- May take a few treatments for heavy infestations
5. Empero Herbicide
Empero is a professional herbicide from PBI Gordon that shares the same active ingredient as Sedgehammer — halosulfuron-methyl — but is formulated for slightly different use patterns, including use on ornamental turf and rights-of-way. It provides excellent systemic control of both yellow and purple nutsedge and moves through the plant into the tuber system, preventing regrowth.
Empero is well suited for lawn care professionals treating larger areas. Like Sedgehammer, it's safe on a wide range of warm-season and cool-season grasses, though it does not include a built-in surfactant — you'll need to add one separately. Apply when nutsedge is actively growing, spacing repeat applications 6–8 weeks apart for persistent infestations.
Pros
- Same active ingredient as Sedgehammer — proven formula
- Controls both yellow and purple nutsedge
- Effective on cool & warm-season turf
- Good for larger lawn areas
Cons
- No built-in surfactant — must add separately
- Less widely available than Sedgehammer
- Overkill for small residential patches
🧮 Herbicide Mixing Rate Calculator
Enter your lawn size and choose your product to get the exact amount of herbicide to mix. Rates are based on product labels — always verify against your specific bottle.
⚠️ Always verify mix rates against your specific product label. Application rates vary by infestation severity. This calculator uses standard label rates for spot/broadcast treatment.
Best Time to Apply Nutsedge Killer
Timing is critical with nutsedge herbicides. Applying at the wrong time of year — or when the weed is dormant — wastes product and money. Here's what each season looks like:
Nutsedge is actively growing but still small (2–6 inches tall). Herbicide is most effective when plants are young and actively translocating to roots. Soil temps are above 65°F.
Apply Sedgehammer, Tenacity, or Certainty now for best kill rate.
Still effective, especially for follow-up applications. Nutsedge is taller but still actively feeding. Hot weather speeds results but avoid applying in extreme heat (above 90°F).
Ideal for 2nd application 6–8 weeks after spring treatment.
Nutsedge is storing energy in nutlets for winter. Herbicide uptake slows as temperatures drop. Some systemic products still work — results may take longer to show.
Best used for clean-up of missed patches. Expect slower results.
Nutsedge is dormant. Applying herbicide during dormancy wastes product entirely — the plant isn't absorbing or translocating anything. Wait until spring emergence.
Plan and purchase products now, apply when weeds emerge in spring.
For maximum effectiveness with Sedgehammer and Tenacity, apply when nutsedge is between 1–3 inches tall. At this stage, the plant is actively growing and moving nutrients (and herbicide) to its root system most aggressively.
Full Comparison: All 5 Nutsedge Killers
| Product | Active Ingredient | Targets | Application | Best For |
|---|---|---|---|---|
| SedgeHammer Plus | Halosulfuron-methyl | Yellow & purple nutsedge, 30+ weeds | Post-emergence | St. Augustine, Bermuda, Bluegrass |
| Tenacity | Mesotrione | Broadleaf weeds, crabgrass, yellow nutsedge | Pre & post-emergence | Cool & warm-season turf |
| Certainty | Sulfosulfuron | Broadleaf, grassy weeds, yellow nutsedge | Post-emergence | Warm-season grasses only |
| Ortho Nutsedge Killer | Sulfentrazone | Nutsedge, chickweed, spurge, clover | Ready-to-use | Small areas, cool & warm-season |
| Empero | Halosulfuron-methyl | Yellow & purple nutsedge, broadleaf weeds | Post-emergence | Large areas, wide turf range |
Key Differences at a Glance
Use this table to quickly narrow down which product fits your situation based on grass type, readiness, and surfactant requirements.
| Product | Active Ingredient | Pre/Post | Warm ✓ | Cool ✓ | Surfactant | RTU |
|---|---|---|---|---|---|---|
| SedgeHammer Plus | Halosulfuron-methyl | Post | ✓ | ✓ | ✓ Built-in | ✗ |
| Tenacity | Mesotrione | Both | ✓ | ✓ | ✗ Add NIS | ✗ |
| Certainty | Sulfosulfuron | Post | ✓ | ✗ | ✗ Add NIS | ✗ |
| Ortho Nutsedge Killer | Sulfentrazone | Post | ✓ | ✓ | ✓ | ✓ RTU |
| Empero | Halosulfuron-methyl | Post | ✓ | ✓ | ✗ Add NIS | ✗ |
SedgeHammer Plus and Empero share the same active ingredient but SedgeHammer has the edge for residential use thanks to its built-in surfactant. Tenacity is the only dual-action option, letting you treat at seeding time. Certainty is best for warm-season lawns with mixed weed problems. Ortho wins on convenience — grab it today, spray tomorrow.
Frequently Asked Questions
Nutsedge reproduces through underground tubers (nutlets) that can survive winter temperatures and re-sprout in spring. A single plant can produce hundreds of nutlets per season. Even if you kill the visible plant, surviving nutlets in the soil will sprout new plants. This is why systemic herbicides like Sedgehammer (which move into the tuber) are far more effective than contact killers, and why a second application 6–8 weeks after the first is strongly recommended.
Glyphosate (Roundup) will temporarily burn back nutsedge tops, but it does not kill the tubers underground. The plant typically re-sprouts within a few weeks. For actual control, you need a selective herbicide like halosulfuron-methyl (Sedgehammer), mesotrione (Tenacity), or sulfentrazone (Ortho Nutsedge Killer) that moves systemically into the root system.
Most nutsedge herbicides are safe once dry — typically 30 minutes to 1 hour after application. However, always check the specific product label for re-entry intervals. Sedgehammer and Tenacity have relatively low toxicity profiles and are safe for lawns once the spray has dried completely. Keep children and pets off the treated area until fully dry and the lawn has been mowed once.
No — most nutsedge herbicides need at least 4–6 hours of dry weather after application to be absorbed by the plant. Rain immediately after spraying will wash the product off the leaves before it can be translocated to the roots. Check the forecast and apply on a calm, dry day with no rain expected for 6–8 hours. Morning application is ideal to avoid afternoon thunderstorms in summer.
For light infestations, a single well-timed application of Sedgehammer or Tenacity in late spring is often enough. For moderate to heavy infestations, plan for two applications spaced 6–8 weeks apart. In extreme cases (lawns overtaken by nutsedge), you may need to treat consistently for 2–3 growing seasons to exhaust the nutlet bank in the soil. Pair herbicide treatments with proper lawn care — dense, healthy turf is the best long-term defense.
Sedgehammer Plus is labeled as safe on most common turf types including bermudagrass, zoysiagrass, St. Augustinegrass, centipedegrass, Kentucky bluegrass, tall fescue, fine fescue, and perennial ryegrass. Always confirm your specific grass type against the current product label before applying, as formulations can change.