How to Get Rid of Nutgrass in Houston & Sugar Land Lawns
What actually works here — and what doesn't
If you've been fighting nutgrass all summer, you're not alone.
It grows faster than your St. Augustine. It pops back up no matter how much you pull it. And most lawn weed killers don't touch it.
Here's the straight answer, without the guesswork.
First: What nutgrass really is (this matters)
This is purple nutsedge or nut grass. What are you looking for? Triangular stem (you can feel it if you roll it between your fingers)
That distinctive umbrella-shaped seed head with multiple radiating branches
Purple/reddish-brown color on the seed head
Narrow leaves
Nutgrass (also called nutsedge) is not a grass and not a broadleaf weed.
It's a sedge.
That's why:
Weed & feed doesn't work on it
Regular lawn weed killers don't work
Pulling it makes it worse
Nutgrass spreads underground by little nut-like tubers. Pull the top, leave the nuts behind, and you get 2-3 new shoots from each one.
There are two types you'll see in Houston:
Yellow nutsedge (most common)
Purple nutsedge (wetter areas)
Both grow way faster than your lawn. That's why they stick up above your mow line 2-3 days after you cut.
Why nutgrass loves Houston & Sugar Land
Our conditions are basically perfect for it:
Warm nights year-round
Heavy clay soil
Frequent irrigation (especially in newer neighborhoods)
Poor drainage in low spots
New sod and disturbed soil
I see it most in:
Lawns on daily watering schedules
New sod (first 1-2 years)
Low spots that stay wet
Areas around sprinkler heads
New construction neighborhoods
If your soil stays wet more than 6-8 hours after watering, nutgrass thrives.
What NOT to do (save your time and money)
❌ Don't pull it
You'll leave the nuts behind. Each nut sprouts 2-3 new shoots. You just made it worse.
❌ Don't use weed & feed
Wrong category. Nutgrass is a sedge, not a grass or broadleaf. Weed & feed won't touch it.
❌ Don't blanket spray weekly
You'll stress your St. Augustine and still not control the nutgrass. This is a spot treatment situation.
❌ Don't expect instant results
This takes time. Anyone who tells you one spray fixes it is lying.
What DOES work: Sedgehammer
Here’s my Amazon store with the nutgrass products that have worked most consistently for Houston and Sugar Land lawns.
I only included sedge-specific options that are safe for St. Augustine and Bermuda when used correctly.
After 30+ years working lawns in Fort Bend County, here's what we've seen work consistently.
Use Sedgehammer herbicide. Plus a Surfactant. That’s it.
That's it. That's the product.
Sedgehammer contains halosulfuron, which is:
Safe on St. Augustine (even in Houston heat)
Kills the nuts underground (not just the top)
Slow and steady (10-14 days to see results)
The most turf-safe option for homeowners
Two versions: Which one do you need?
Sedgehammer Plus (for small yards or spot treatments)
Comes in 13.5 gram packets
Each packet treats 1,000 sq ft
Surfactant already included (easier)
Mix one packet in 1 gallon of water
Good for most homeowners
Regular Sedgehammer (for larger areas)
Comes in 1.33 oz bottle
Treats up to 40,000 sq ft
You must add surfactant separately
More economical for bigger lawns
If you've got a small yard or just a few nutgrass patches, go with Sedgehammer Plus. It's simpler.
Get a surfactant!
Why a surfactant matters (and why nutgrass keeps “winning”)
Nutgrass leaves are naturally waxy and slick.
That waxy coating is the plant’s built-in defense system.
When you spray herbicide without a surfactant, the liquid beads up and rolls right off the leaf — meaning very little product actually enters the plant. That’s why so many homeowners say, “I sprayed and nothing happened.”
A surfactant (also called a spreader-sticker) breaks that surface tension.
In plain terms:
It helps the spray spread evenly across the leaf
It helps the herbicide stick instead of sliding off
It allows the product to soak into the plant, where it can do its job
Without a surfactant, even the correct herbicide often underperforms.
When you need a surfactant (and when you don’t)
SedgeHammer Plus → Surfactant already included
This is why it’s easier for most homeowners and better for spot treatments.Regular SedgeHammer → You must add surfactant separately
Skipping this step is one of the most common reasons nutgrass survives.
If the label doesn’t clearly say “includes surfactant,” assume you need one.
How to use surfactant correctly
Add the surfactant to the spray tank after the herbicide
Follow the surfactant label rate — more is not better
Spray until the leaves are evenly coated, not dripping
You want coverage, not runoff.
The takeaway
Nutgrass control fails most often because:
The wrong product was used
Or the right product was used without a surfactant
That’s why nutgrass feels like it’s “winning.”
Not because it’s unbeatable — but because the details matte
How to apply it (step by step)
1. Wait for the right stage
Don't spray tiny nutgrass. Wait until it's 3-8 leaves tall (usually 4-6 inches). That's when it's actively growing and absorbing herbicide best.
2. Pick a good day
Early morning (before 9am) or evening
Calm (no wind)
No rain expected for 24 hours
If it's been dry, water your lawn a few hours before spraying
3. Mix it (this step matters)
If your sedge product does not say “surfactant included,” you must add one or the treatment will underperform.
Follow the label exactly:
SedgeHammer Plus:
• 1 packet per gallon of water
• Surfactant already included — no extra neededRegular SedgeHammer:
• Use the measuring scoop provided
• Add a non-ionic surfactant (this is required)
Mixing order (important):
Fill the sprayer halfway with water
Add the SedgeHammer and mix well
Add the surfactant
Top off with water and gently agitate
Do not skip the surfactant when using regular SedgeHammer.
Nutgrass leaves are waxy, and without a surfactant the spray beads up and runs off instead of soaking in.
More product does not equal better results — correct mixing does.
Follow the label exactly:
Sedgehammer Plus: 1 packet per gallon of water
Regular Sedgehammer: Use the measuring scoop provided
4. Spot spray the nutgrass
Spray directly on the nutgrass leaves
Get them wet, but don't drench
Mark your patches first if it helps (wire flags work)
Avoid overspray on good turf
5. Don't mow
Wait 2 days before spraying
Wait 2 days after spraying
The herbicide needs time on the leaf
6. Be patient
7-10 days: yellowing starts
10-14 days: visible decline
3-4 weeks: new shoots may appear (from remaining nuts)
This is normal. You're not done yet.
You'll need 2-3 treatments (this is normal)
Nutgrass doesn't die in one round.
First treatment: Knocks back what's above ground and starts killing the nuts.
Second treatment (6-10 weeks later): Catches stragglers and any nuts that sprouted late.
Third treatment (if needed): For heavy infestations.
This is not a failure on your part. This is how nutgrass control works.
What about Houston heat?
Good news: Sedgehammer is safe on St. Augustine even in our summer heat.
Some nutsedge products (like Dismiss or Blindside) will fry your St. Augustine in 90°+ weather.
Sedgehammer won't.
Best practice:
Spray early morning (before it gets hot)
Or spray in the evening
Water your lawn a few hours before if it's been dry
I've used Sedgehammer on St. Augustine in July and August with no turf damage.
Optional: Stop it from coming back
Herbicides fix what's there. These habits reduce how fast it returns:
Water smarter
1" per week total (including rain)
2-3 sessions per week max
Let soil dry between waterings
Don't water every day
Daily irrigation is the #1 cause of nutgrass I see in new neighborhoods.
Fix drainage
If water pools for more than a few hours, you've got a nutgrass breeding ground.
Mow taller
Keep St. Augustine at 3.5-4" in summer
Taller grass shades soil
Makes it harder for nutgrass to compete
What about Kyllinga?
If you've got tiny clover-looking stuff that's actually a sedge, that's kyllinga (also called green kyllinga).
It forms low, dense mats.
Good news: Sedgehammer works on kyllinga too.
Same process. Same patience required.
The bottom line
Nutgrass control works when you:
Use Sedgehammer (the right category of product)
Use a surfactant to help the herbicide work
Spot spray (not the whole lawn)
Wait for it to work (10-14 days per treatment)
Expect 2-3 treatments (spaced 6-10 weeks apart)
Fix your watering habits (so it doesn't come back)
That's it. No shortcuts. No magic products.
This is a 4-8 week process. But if you follow the steps above, it works.
What you need to buy
Here's the simple shopping list:
For small yards (under 5,000 sq ft):
Sedgehammer Plus (13.5g packets) — surfactant included
Blue spray marker dye (optional but helpful)
For larger yards:
Sedgehammer herbicide (1.33 oz bottle)
Non-ionic surfactant (like Southern Ag or Hi-Yield)
Blue spray marker dye (optional)
Safety gear:
That's it. Keep it simple.
Need help?
If you've got nutgrass questions specific to your Sugar Land or Houston lawn, ask us here.
We've been dealing with nutgrass in Fort Bend County since 1991.
— Todd Farber
Garden Guy
Sugar Land, Texas
Amazon Links You'll Need
Sedgehammer Products:
Sedgehammer Plus (13.5g packets with surfactant included)
Sedgehammer Herbicide (1.33 oz bottle — for larger yards)
Application Tools: 3. 1-2 gallon pump sprayer 4. Blue spray marking dye
If using regular Sedgehammer (not Plus): 5. Southern Ag Surfactant (non-ionic) 6. Hi-Yield Spreader Sticker (alternative surfactant)
Safety: 7. Chemical-resistant gloves 8. Safety glasses
Look, nutgrass is frustrating. But it's beatable.
I know this feels like a lot of steps for one weed. And I know it's tempting to just throw the kitchen sink at it — multiple products, higher rates, whatever it takes.
But here's the truth: Sedgehammer works. It just takes patience and a couple of repeat treatments.
Most people quit after the first spray because they don't see instant results. Or they pull it between treatments and restart the whole cycle.
Stick with the plan. Give it the full 6-10 weeks. Fix your watering schedule. And you'll get there.
I've seen it work hundreds of times in Sugar Land and Houston lawns. Your yard isn't different.
You've got this.
Email me right here for more help: Garden Guy
Todd Farber is a Texas A&M horticulturist and longtime Texas garden guy with over 33 years of hands-on experience working in Houston soils. He’s still the boots-on-the-ground guy today—designing, digging, and walking yards with homeowners.
