Nut Grass (Nutsedge): How to Identify It and Kill It in Your Lawn

Key takeaways

• Nut grass is not a grass. Yellow nutsedge (Cyperus esculentus) and purple nutsedge (C. rotundus) have solid triangular stems and leaves in threes, so crabgrass and dandelion sprays miss them (Purdue TURF-45).
• One yellow nutsedge tuber produced 1,900 shoots and 6,900 tubers in a year in a Minnesota trial (Purdue Landscape Report), and UF/IFAS puts a season’s output at 4 to 12 million tubers per acre (UF/IFAS ENH1305).
• Spray before the fifth leaf: after that stage, UC IPM says sedge herbicides kill the leaves but not the tubers (UC IPM pn7432). Nebraska Extension sets June 21 as the yellow nutsedge deadline because new tubers start then (UNL).
• Grass type picks the product. UGA rates halosulfuron safe on all 7 common lawn grasses it lists, but St. Augustinegrass is sensitive to sulfentrazone and Kentucky bluegrass and tall fescue to imazaquin (UGA Bulletin 978).
• Expect 2 to 3 years: Purdue says that is how long herbicide programs take to cut viable tubers in the soil by 90 percent (Purdue).

What is nut grass, and is it really a grass?

Nut grass is the common name for two perennial sedges, yellow nutsedge (Cyperus esculentus) and purple nutsedge (Cyperus rotundus). Neither is a grass: Purdue Extension notes the triangular stem you can feel by rolling it between your fingers, leaves arranged in threes, and a glossy, hairless leaf (Purdue TURF-45). The “nuts” are tubers on underground rhizomes, which is why the plant returns after mowing, pulling and frost.

Measure	Value	Source
Height, unmowed	Up to 36 in (both species)	UF/IFAS ENH1305
Yellow nutsedge leaf	About 0.5 in wide, 12 to 35 in long, long tapered tip	UF/IFAS
Purple nutsedge leaf	0.2 to 0.5 in wide, abruptly pointed tip, darker green	UF/IFAS
Tubers per plant per summer	Several hundred (yellow)	Purdue
One tuber, one year (Minnesota trial)	1,900 shoots and 6,900 tubers	Purdue Landscape Report
Tubers per acre per season	4 to 12 million	UF/IFAS
Tuber formation begins	4 to 6 weeks after emergence	UF/IFAS
Rhizome depth	8 to 14 in; most tubers in the top 6 in	UC IPM
Tuber life in soil	1 to 3 yr (UC IPM); more than 3 yr (Purdue)	UC IPM; Purdue
Soil temperature for sprouting	Above 43°F yellow; above 59°F purple	UC IPM
Patch size	Up to 10 ft across	UC IPM
U.S. range	Yellow: 48 states; purple: mainly Virginia to central Texas, plus AZ, CA, OR	UNL; UF/IFAS

Nut grass grows fastest in summer heat, when cool-season lawns slow down, so it shows up as pale, upright tufts 2 or 3 days after mowing. In Indiana, Purdue says yellow nutsedge emerges from tubers in late April or May, about 2 weeks after crabgrass, and grows until the first frost. Frost kills the leaves, not the tubers that make next year’s crop.

The two species split by climate. NC State TurfFiles calls yellow nutsedge a North American native and one of the more cold-tolerant sedges (TurfFiles: yellow nutsedge), while purple nutsedge, native to India, is less cold tolerant and mostly a warm-season turf problem (TurfFiles: purple nutsedge). Nebraska Extension documents yellow nutsedge in 48 states, including Alaska.

How fast does nut grass spread?

Fast, and mostly underground. In a Minnesota field trial cited by Purdue, one yellow nutsedge tuber produced 1,900 shoots and 6,900 new tubers in a single season, and the Connecticut Agricultural Experiment Station repeats the same study’s figures (CAES fact sheet). Seed matters little: UT Extension says nutsedge seedheads contain few viable seeds, so tubers and rhizomes do the spreading.

1. Starting tuber1
2. Shoots after 1 year1,900
3. New tubers after 1 year6,900

Source: Tumbleson and Kommedahl (1961), as cited by the Purdue Landscape Report (Sept. 10, 2018) Values match the spread table below the chart.

Show the numbers

	Count
Starting tuber	1
Shoots after 1 year	1,900
New tubers after 1 year	6,900

Starting point	Result after one growing season	Where	Source
1 yellow nutsedge tuber	1,900 shoots and 6,900 tubers	Minnesota field trial (Tumbleson and Kommedahl, 1961)	Purdue Landscape Report; CT Agricultural Experiment Station
1 yellow nutsedge plant	Several hundred tubers	Indiana lawns	Purdue TURF-45
1 acre of yellow or purple nutsedge	4 to 12 million tubers	Field studies cited by UF/IFAS	UF/IFAS ENH1305
1 green kyllinga plant	100+ flowers and up to 5,000 seeds	California	UC IPM pn7459

How do you tell yellow nutsedge, purple nutsedge and kyllinga apart?

Dig one plant and look at the tubers. Yellow nutsedge forms one tan to brown tuber at the tip of each rhizome; purple nutsedge forms tubers in chains along the rhizome, covered in red to brown papery scales; green kyllinga forms no tubers at all (UF/IFAS ENH1305; UC IPM pn7459). Above ground, check the seedhead color and the leaf tip.

Feature	Yellow nutsedge (Cyperus esculentus)	Purple nutsedge (Cyperus rotundus)	Green kyllinga (Kyllinga brevifolia)	Source
Tubers	One per rhizome tip; round, hard, 0.1 to 0.6 in, brown to black	Chains along the rhizome; 0.1 to 1.0 in long, red to brown papery scales	None; rhizomes only	UF/IFAS; UC IPM
Tuber taste	Little taste to slightly sweet (NC State); almond (UC IPM)	Bitter, peppery	No tubers	TurfFiles; UC IPM
Seedhead	Loose, yellow-brown to straw or golden spikelets	Loose, reddish-purple spikelets	Round green head about 3/8 in wide on a 2 to 8 in stalk	TurfFiles; UC IPM
Leaf tip	Long, gradually tapered	Blunter, abruptly pointed	Fine, short leaves	UF/IFAS; UT W260
Leaf color	Light green to yellow-green, glossy	Dark green	Similar to yellow nutsedge, finer and shorter	UT W260; TurfFiles
Growth habit	Single upright plants above the turf	Single upright plants	Dense mats; flowers even at 3/4 in mowing	UC IPM
Cold tolerance	High; the northern nutsedge	Low; mainly the South and Southwest	Southeast to California, spreading	TurfFiles; TurfFiles
Ease of control	Easier	Much harder	Hard once mats form	TurfFiles; TurfFiles

Young plants of the two nutsedges look alike, UF/IFAS warns, so wait for a seedhead or dig for tubers before buying a product. Tennessee Extension’s W260 adds that kyllinga can survive mowing under 0.25 inch and spreads by short rhizomes into mats, where the nutsedges stand as scattered single shoots. Kyllinga also blooms in a mowed lawn; the nutsedges rarely do.

Two other look-alikes show up in wet lawns. UC IPM lists tall flatsedge (Cyperus eragrostis), a tight clump under 1 foot across with no tubers, and UF/IFAS shows globe sedge (Cyperus croceus), which is often mistaken for yellow nutsedge. For grassy weeds that also stand above the lawn, our common lawn weeds chart sorts sedges from grasses and broadleaves.

Why does pulling nut grass make it worse?

Pulling removes the shoot but leaves the tubers and rhizomes, 8 to 14 inches down in UC IPM’s figures. Purdue says hand pulling “will not remove the tubers in the soil”, and UC IPM says a mature tuber can resprout more than 3 times (Purdue TURF-45; UC IPM pn7432). After a pull, each buried tuber sends up a fresh shoot, which reads as more nut grass.

Pulling works only on young plants and only if you keep at it. UC IPM’s rule is to remove plants before they have 5 to 6 leaves, which in summer means every 2 to 3 weeks, because tubers have not formed yet. The first shoot uses 60 percent of a tuber’s reserves and the second 20 percent, so repeated removal starves it. In turf, UC IPM says to dig out small patches at least 8 inches deep, refill and reseed or sod.

Common claim	What the primary source says	Source
“Pulling one plant makes 3 to 5 new ones”	No extension figure found for that ratio. Purdue: pulling leaves tubers in the soil; UC IPM: mature tubers resprout 3+ times	Purdue; UC IPM
“Tubers last up to 10 years”	Up to 10 years (Purdue Landscape Report, 2018); 1 to 3 years for most tubers (UC IPM); more than 3 years (Purdue TURF-45)	Purdue LR; UC IPM
“Yellow nutsedge tubers are oblong and hairy”	Round, hard and smooth, scaly only when immature (UF/IFAS); round and smooth, up to 7/16 in (UC IPM)	UF/IFAS; UC IPM
“Spray before June 21” for every nutsedge	UNL’s June 21 date is for yellow nutsedge; Arizona sprays purple nutsedge with burndown before the solstice and ALS herbicides after it	UNL; Arizona AZ1818
“Mow high to beat nutsedge”	UNL: mow cool-season lawns at 3 to 3.5 in; Arizona: frequent low mowing in spring weakens purple nutsedge in warm-season turf	UNL; Arizona
“Landscape fabric stops it”	Black or clear plastic does not (leaf tips pierce it); nonwoven or woven polypropylene fabric under mulch suppresses it	UC IPM; UF/IFAS

What kills nut grass in a lawn without killing the grass?

A sedge herbicide whose label lists both nutsedge and your lawn grass. For homeowners that usually means halosulfuron (SedgeHammer, EPA Reg. No. 81880-1) or sulfentrazone (Ortho Nutsedge Killer for Lawns, 239-2793), the two actives Purdue recommends (Purdue TURF-45). Broadleaf mixes and crabgrass killers do not touch nutsedge unless they add sulfentrazone, and Purdue rates those four-way mixes only fair.

The table compares 11 current EPA-accepted labels we downloaded from the EPA Pesticide Product Label System in October 2026. Rates are the lawn rates per 1,000 sq ft printed on each label; where a label gives only a per-acre figure, we converted it at 43,560 sq ft per acre. The label in your hand is the legal instruction, and it can differ from the version on file.

Product (EPA Reg. No.)	Active ingredient	Sedges on the label	Lawn rate per 1,000 sq ft	Repeat and yearly limit	Lawn grasses to watch	Label
SedgeHammer (81880-1)	Halosulfuron-methyl 75%	Yellow, purple, green kyllinga	0.9 g scoop in 1 gal water + 2 tsp nonionic surfactant	4 weeks apart; max 4 a year and 5 1/3 oz product per acre per 12 months	None excluded; 12 grasses listed incl. St. Augustine, centipede, tall fescue	Sept. 1, 2026
SedgeHammer+ (81880-24)	Halosulfuron-methyl 5%, surfactant built in	Yellow, purple, green kyllinga (2 applications)	0.5 oz (13.5 g) pouch in 1 gal water	14 days minimum; second spray often 6 to 10 weeks; max 4 a year	None excluded; adds buffalograss	Aug. 28, 2020
Ortho Nutsedge Killer for Lawns RTS2 (239-2793)	Sulfentrazone 1.4%	Yellow, purple (spot retreat), green kyllinga, globe sedge	1 qt covers 5,000 sq ft; max 6.4 fl oz per 1,000 sq ft	Max 9.3 fl oz per 1,000 sq ft a year; New York: 1 application a year	15 grasses listed incl. St. Augustine; home lawns only	Dec. 9, 2025
Image consumer concentrate (73342-4)	Imazaquin 3.3%	Yellow, purple, green kyllinga, globe sedge	Up to 4 fl oz; spot mix 2.5 fl oz in 1 gal	Second spray at 6 weeks; max 2 a year, 8 fl oz per 1,000 sq ft	Only bermuda, St. Augustine, buffalo, zoysia, centipede; injures tall fescue; kills bahia and ryegrass	Aug. 30, 2024
Basagran T&O (7969-326)	Bentazon 44%	Yellow only; label says purple is not controlled	0.75 fl oz (5 tsp) in 1 to 2 gal at 6 to 8 in tall	2 sprays 7 to 10 days apart; max 1.5 fl oz per 1,000 sq ft a year	None excluded; no mowing 5 days before or after (residential)	Sept. 11, 2024
Dismiss Turf (101563-284, label printed as 279-3295)	Sulfentrazone 39.6%	Yellow, purple (split), green kyllinga, globe sedge	Cool-season 0.092 to 0.18 fl oz; warm-season 0.18 to 0.275 fl oz; no surfactant	Purple: second spray 35 days later; max 0.375 lb sulfentrazone per acre a year	May discolor St. Augustine and some zoysia, bahia; injury on some fescue cultivars	July 18, 2024
Dismiss NXT (101563-315)	Sulfentrazone 31.77% + carfentrazone 3.53%	Yellow, purple (split), green kyllinga, globe sedge	Cool-season 0.115 to 0.230 fl oz; warm-season 0.230 to 0.344 fl oz	Purple: second spray 35 days later	Same discoloration notes as Dismiss	April 1, 2026
Celero (59639-155, label text V-10142)	Imazosulfuron 75%	Yellow, purple, annual kyllinga	Spot: 0.25 to 0.33 oz in 1 to 2 gal + 2 tsp surfactant per gal	21 days apart; max 2 a year, 28 oz per acre	Bahia, seashore paspalum, buffalo not listed; spray only at 65 to 90°F highs	April 17, 2020
Vexis liquid (2217-1072)	Pyrimisulfan 1.24%	Yellow, purple, green kyllinga (repeat may be needed)	1.2 to 1.7 fl oz	30 days apart; max 2.5 fl oz per 1,000 sq ft a year	Floratam and Bitterblue St. Augustine listed after 7 nights above 50°F; no carpetgrass	April 17, 2026
Tenacity (100-1267)	Mesotrione 40%	Yellow only (postemergence)	0.092 to 0.184 fl oz + surfactant; spot 1 tsp in 2 gal	Second spray 2 to 3 weeks; 14 days minimum; max 2 a year	Bermuda, zoysia, bentgrass, seashore paspalum sensitive; St. Augustine only grown for sod	Sept. 28, 2022
Certainty (59639-226)	Sulfosulfuron 75%	Yellow, purple, green kyllinga, globe sedge	Hand sprayer: 0.8 g scoop in 2 gal at 2 gal per 1,000 sq ft + surfactant	4 weeks apart; max 2 a year	Kills tall fescue and perennial ryegrass; St. Augustine may be more sensitive	Nov. 7, 2024

Three label details change what you buy. The Basagran T&O label says outright that purple nutsedge is not controlled, and the Tenacity label lists only yellow nutsedge, so both fail in the Deep South and the Southwest where purple dominates. The Image label covers purple nutsedge but only on bermuda, St. Augustine, buffalo, zoysia and centipede lawns. Halosulfuron is the one active with no lawn grass excluded on its label.

Several of these are professional products. UC IPM marks Certainty, Monument, Tenacity and Dismiss CA as not available to home gardeners (UC IPM pn7432), and anyone spraying a customer’s lawn for pay needs a state applicator license; our pesticide applicator license guide covers the categories. Product-by-product prices for the homeowner sizes are in our lawn weed killer comparison.

Which nutsedge herbicides are safe on St. Augustine, centipede, bermuda and fescue?

Halosulfuron and bentazon are the only sedge actives that UGA’s Bulletin 978 rates tolerant on all 7 lawn grasses in its grid. St. Augustinegrass is rated sensitive to sulfentrazone, tall fescue sensitive to sulfosulfuron and imazaquin, and bahiagrass sensitive to imazaquin (UGA B-978, p. 10). Read the grid with the label: Dismiss lists St. Augustine with a discoloration warning, which UGA treats as a do-not-use.

Active (example product)	Kentucky bluegrass	Bermuda	Bahia	Centipede	Tall fescue	St. Augustine	Zoysia
Halosulfuron (SedgeHammer)	T	T	T	T	T	T	T
Bentazon (Basagran T&O)	T	T	T	T	T	T	T
Sulfentrazone (Dismiss, Ortho Nutsedge Killer)	T	T	T	T	I	S	T
Sulfosulfuron (Certainty)	T	T	I	T	S	T	T
Imazaquin (Image)	S	T	S	T	S	T	T
Trifloxysulfuron (Monument)	S	T	S	S	S	S	T
Glyphosate (Roundup)	S	T only when dormant	S	S	S	S	S

Grass-specific notes from the labels fill the gaps. Vexis is the only label in our set that names Floratam and Bitterblue St. Augustine, with a condition: spray after 7 nights in a row above 50°F (EPA 2217-1072). Tenacity allows St. Augustine only when grown for sod and calls bermuda and zoysia sensitive. Our profiles of St. Augustine grass and centipede grass carry each grass’s other herbicide limits.

Which products work on purple nutsedge and kyllinga?

Purple nutsedge and kyllinga are where products split. Tennessee Extension rated all 10 sedge products in its table excellent on yellow nutsedge, but on kyllinga SedgeHammer rated poor (60 percent or less) while Celero, Image, Katana and Monument rated excellent (UT W260, Table 1). For purple nutsedge, Arizona Extension found SedgeHammer, Scepter and Vexis held 2 to 4 weeks, and Monument, Katana, Certainty and Celero held longer than 4 to 6 weeks (AZ1818).

1. Celero90
2. Image90
3. Katana90
4. Monument90
5. Certainty80
6. Dismiss80
7. Dismiss NXT80
8. Dismiss South80
9. SedgeHammer60

Source: University of Tennessee Extension W260, Table 1 E = 90 to 100%, G = 80 to 90%, P = 60% or less (plotted at 60 as an upper bound). All nine rated E on yellow nutsedge. Values match the efficacy table.

Show the numbers

	Minimum % control implied by UT rating
Celero	90
Image	90
Katana	90
Monument	90
Certainty	80
Dismiss	80
Dismiss NXT	80
Dismiss South	80
SedgeHammer	60

Product	Active	Yellow nutsedge	Kyllinga	Labeled turf species in UT’s table	Source
Celero	Imazosulfuron	E	E	Bermuda, zoysia, centipede, St. Augustine, bentgrass, fine fescue, Kentucky bluegrass, ryegrass, tall fescue	UT W260
Image	Imazaquin	E	E	Bermuda, zoysia, centipede, St. Augustine, seashore paspalum	UT W260
Katana	Flazasulfuron	E	E	Bermuda, zoysia, centipede, seashore paspalum	UT W260
Monument	Trifloxysulfuron	E	E	Bermuda, zoysia	UT W260
Certainty	Sulfosulfuron	E	G	Bermuda, zoysia, centipede, St. Augustine, seashore paspalum	UT W260
Dismiss	Sulfentrazone	E	G	Cool- and warm-season incl. St. Augustine	UT W260
Dismiss NXT	Sulfentrazone + carfentrazone	E	G	Cool- and warm-season incl. St. Augustine	UT W260
Dismiss South	Sulfentrazone + imazethapyr	E	G	Bermuda, zoysia, centipede	UT W260
SedgeHammer	Halosulfuron	E	P	Cool- and warm-season incl. St. Augustine	UT W260

Speed differs as well. Purdue says sulfentrazone shows injury on yellow nutsedge within a few days and halosulfuron in about 2 weeks; UT puts complete desiccation at about 1 week for the Dismiss products and 3 to 4 weeks for SedgeHammer and Celero. Arizona adds a resistance rule for purple nutsedge: limit ALS-inhibiting herbicides, the group that includes halosulfuron, imazosulfuron and pyrimisulfan, to two summer applications.

When is the best time to spray nutsedge?

Spray yellow nutsedge in late spring to early summer, after most shoots are up but before June 21, and again 4 to 8 weeks later if it regrows. Nebraska Extension picked June 21, the longest day, because that is when the plant starts new tubers 8 to 14 inches down (UNL). NC State says new tubers are added from late June and early July (TurfFiles).

Leaf count is the field version of the same rule. UC IPM says the sedge herbicides must go on before the fifth-leaf stage, while the plant is still sending sugars from the leaves to new tubers; after that, “the herbicide will kill only the aboveground portion” (UC IPM pn7432). UGA’s halosulfuron window is the 3 to 8 leaf stage (UGA B-978), and the CAES Connecticut fact sheet uses the same 3 to 8 leaves.

Purple nutsedge in the low desert runs on a different calendar. Arizona Extension starts in spring with sulfentrazone burndown sprays every 7 to 14 days plus frequent low mowing, then switches to ALS herbicides (halosulfuron, imazosulfuron, sulfosulfuron, trifloxysulfuron and others) around July 4, with a second spray 4 to 6 weeks later. After the solstice, shorter days push sugars down to the developing tubers and the herbicide goes with them (Arizona AZ1818).

When	Yellow nutsedge (cool-season and transition lawns)	Purple nutsedge (warm-season lawns)	Source
Soil above 43°F / 59°F	Tubers begin to sprout above 43°F; Indiana emergence late April to May	Tubers sprout above 59°F; Arizona emergence from February or March	UC IPM; Purdue; Arizona
3 to 8 leaves, May to mid-June	First halosulfuron or sulfentrazone spray	Sulfentrazone burndown every 7 to 14 days, plus frequent low mowing	UGA; Arizona
By June 21	First spray should be down; new tubers start	Solstice: switch point	UNL; Arizona
Late June to early July	Tuber production begins (NC State)	First ALS herbicide spray around July 4	TurfFiles; Arizona
4 to 8 weeks after first spray	Repeat if plants regrow (Purdue); mid-July (UNL); 6 to 10 weeks (UGA)	Second ALS spray 4 to 6 weeks later, about mid-August; stop at 2 ALS sprays a summer	Purdue; UGA; Arizona
Early August to September	Visible new tubers at rhizome tips (Connecticut)	Tubers maturing; judge results next spring	CAES; Arizona
First frost	Leaves die; tubers overwinter	Leaves brown; tubers overwinter	Purdue; UT W260

Heat matters too. Purdue says not to spray when the lawn is drought stressed or the air is 90°F or hotter, “especially sulfentrazone-containing products”, and UGA gives the same 90°F line for all postemergence lawn herbicides. UT Extension limits sedge sprays to actively growing plants, May through August in Tennessee (UT W260).

1. Yellow nutsedge tubers sprout43
2. Purple nutsedge tubers sprout59
3. Green kyllinga seed germinates65
4. Stop postemergence sprays90

Source: UC IPM pn7432 and pn7459; Purdue TURF-45; UGA B-978 Soil temperature for the first three bars, air temperature for the last. Values match the threshold table.

Show the numbers

	Temperature
Yellow nutsedge tubers sprout	43
Purple nutsedge tubers sprout	59
Green kyllinga seed germinates	65
Stop postemergence sprays	90

Threshold	°F	What happens	Source
Yellow nutsedge tubers sprout	43	Soil stays above 43°F; spring emergence starts	UC IPM pn7432
Purple nutsedge tubers sprout	59	Soil stays above 59°F	UC IPM pn7432
Green kyllinga seed germinates	65	Soil about 65°F with adequate moisture	UC IPM pn7459
Stop spraying	90	Air at or above 90°F or drought-stressed turf: skip postemergence sprays	Purdue; UGA B-978

How do you spray nutsedge step by step?

Spray young, actively growing nutsedge on a dry, calm day with the label rate in 1 gallon of water per 1,000 sq ft, add surfactant only where the label calls for it, leave the lawn unmowed for 2 days on each side, and recheck in 4 to 6 weeks. The steps below use the SedgeHammer label (EPA 81880-1) with the sulfentrazone differences noted.

1. Confirm the species. Dig one plant: single tan tubers mean yellow nutsedge; chained tubers with papery scales mean purple; no tubers and a round green head mean kyllinga, where SedgeHammer rated poor in UT trials.
2. Match the label to your grass with UGA Bulletin 978’s tolerance grid. St. Augustine lawns: halosulfuron, not sulfentrazone. Tall fescue lawns: halosulfuron, sulfentrazone or bentazon, never Image or Certainty.
3. Time it. Spray at the 3 to 8 leaf stage (UGA), before June 21 for yellow nutsedge (UNL), with air under 90°F (Purdue) and no rain forecast within 4 hours (SedgeHammer label).
4. Leave the lawn unmowed for 2 days before and 2 days after spraying, as the SedgeHammer label directs; the Basagran residential label says 5 days.
5. Practice with water first. UGA says to spray 1 gallon of plain water over a measured 1,000 sq ft (20 by 50 ft) to learn your walking speed (UGA B-978).
6. Mix one 0.9 g level scoop of SedgeHammer and 2 teaspoons of nonionic surfactant (at least 80 percent active) in 1 gallon of water per 1,000 sq ft, and spray within 24 hours. SedgeHammer+ needs no surfactant: one 0.5 oz pouch per gallon. Purdue says not to add surfactant to sulfentrazone products.
7. Spray the nutsedge leaves evenly until wet, then keep irrigation off for at least 4 hours (CAES fact sheet; the Celero label says 4 hours before and after).
8. Wait. Expect yellowing in about 2 weeks for halosulfuron and complete kill in 3 to 4 weeks; sulfentrazone burns down in about 1 week (UT W260).
9. Recheck at 4 to 6 weeks and spray regrowth (SedgeHammer minimum interval: 4 weeks; Dismiss purple nutsedge split: 35 days). Stop at the yearly limit in the label table.
10. Reseed or sod bare patches only after the label wait: 4 weeks for SedgeHammer, about 1 month for Dismiss and Ortho, 1 1/2 months for Image. Repeat the program the next May; Purdue expects 2 to 3 seasons.

The worked example below scales the label mix to a real lawn. The scoop rate of 0.9 g per 1,000 sq ft equals about 1.38 oz per acre, which is the top of SedgeHammer’s 2/3 to 1 1/3 oz range. That matters for the yearly cap: by our arithmetic, four full-scoop sprays on the same spot total about 5.5 oz per acre, a little over the 5 1/3 oz limit, so plan on three.

Step	Input	Arithmetic	Result
Lawn and patch size	6,000 sq ft lawn; nutsedge patches measured at 800 sq ft	Patch area ÷ 1,000	0.8 treatment units
SedgeHammer product	0.9 g per 1,000 sq ft (label scoop)	0.8 × 0.9 g	0.72 g (a little under one scoop)
Water	1 gal per 1,000 sq ft	0.8 × 1 gal	0.8 gal (about 3 quarts)
Nonionic surfactant	2 tsp per gal	0.8 × 2 tsp	1.6 tsp
Same lawn, broadcast	6,000 sq ft	6 × 0.9 g; 6 × 1 gal; 6 × 2 tsp	5.4 g (6 scoops), 6 gal water, 12 tsp (1/4 cup) surfactant
Per-acre equivalent	0.9 g per 1,000 sq ft	0.9 × 43.56 = 39.2 g ÷ 28.35 g per oz	1.38 oz per acre per spray
Yearly cap check	Label: 5 1/3 oz per acre per 12 months	5.33 ÷ 1.38	3.9 sprays: plan on 3 at the scoop rate
Bottle coverage	1.33 oz bottle = 37.7 g	37.7 ÷ 0.9	About 42 treatments of 1,000 sq ft
Product cost	$64.48 for 1.33 oz (DoMyOwn, Oct. 28, 2026, from our lawn weed killer guide)	$64.48 ÷ 42	About $1.54 per 1,000 sq ft per spray, before surfactant
Sulfentrazone check (Dismiss, warm-season)	Max 12 fl oz per acre per spray; 0.375 lb a year = 12 fl oz of a 4 lb/gal product	12 ÷ 12	One top-rate warm-season spray uses the whole year’s sulfentrazone, so purple nutsedge splits are 8 + 4 or 6 + 6 fl oz

How do you get rid of nutsedge in flower beds and gardens?

In beds, dig or spot-spray rather than rely on mulch. Purdue says to dig around the base and lift the whole plant with its rhizomes (Purdue TURF-45), and UC IPM says a hoe must go 8 to 14 inches deep. Glyphosate works only on young plants and gives “limited suppression” (UC IPM), and it kills any lawn or bed plant it touches.

Method	What it does to nutsedge	Limits	Source
Dig plant, rhizome and tuber	Removes the tuber if you go 8 to 14 in deep	Repeat every 2 to 3 weeks in summer; check for regrowth	UC IPM; Purdue
Glyphosate spot spray	Marginal to limited control; best on young, unmowed plants	Nonselective: kills turf and ornamentals it contacts; not for lawns	Purdue; UC IPM
Halosulfuron (SedgeHammer)	Labeled for nutsedge around established woody ornamentals in landscaped areas	Keep off desirable herbaceous plants; read the label site list	EPA label 81880-1
Preemergents in ornamentals	Dichlobenil, S-metolachlor and dimethenamid-P reduce yellow nutsedge emergence	None controls purple nutsedge; S-metolachlor and dimethenamid-P are professional products	UC IPM
Organic mulch 2 to 3 in	Not effective	Nutsedge grows through pine bark, pine straw and chips	UF/IFAS ENH1305
Black or clear plastic	Does not control	Sharp leaf tips pierce polyethylene	UC IPM
Polypropylene landscape fabric plus mulch	Suppresses both species	Breaks down over time; emerging plants still need removal	UC IPM; UF/IFAS
Shade from tall shrubs or groundcover	Reduces growth	Low groundcovers do not cast enough shade	UC IPM
Summer tilling and drying	Reduces purple nutsedge only	Not effective on yellow; only where nothing needs irrigation	UC IPM

Check soil before it comes in. Purdue TURF-45 says yellow nutsedge tubers move in topsoil and fill dirt during construction and when people divide perennials (Purdue), and UF/IFAS finds both species in containers only when field soil or contaminated compost went into the mix. A bed that sprouts nutsedge the season after new topsoil arrived probably got its tubers from that load, so ask a supplier where the soil was dug before the next delivery.

How do you fix the wet soil that nutsedge loves?

Find the water source first. UC IPM says nutsedge presence “often indicates drainage is poor, irrigation is too frequent, or sprinklers are leaky” (UC IPM pn7432), and Tennessee Extension says long-term control in poorly drained areas is possible only once the drainage problem is fixed (UT W260). Herbicide on a soggy low spot buys one season.

Wet-soil cause	How to confirm it	Fix	Source or GIR guide
Overwatering	Runoff, puddles and sedges after irrigation, the overwatering signs UF/IFAS lists	Water deeply and less often: about 1 in a week, rain included	UNL; our watering guide
Leaking or broken heads	One zone stays green and soggy; catch-cup test shows uneven output	Repair heads and valves before treating	UC IPM
Compacted soil	Screwdriver will not push in; water ponds	Core aerate to reduce compaction	UNL; when to aerate
Low spot or poor grade	Water stands for hours after rain	Regrade or topdress the dip	Leveling or topdressing
Clay or high water table	Water stands after every rain in the same strip	Subsurface drain to a lower outlet	French drain cost
Thin turf mowed too short	Bare soil between grass plants	Mow cool-season turf at 3 to 3.5 in and thicken the stand	UNL; Purdue

Mowing height cuts both ways. Purdue says yellow nutsedge is worst in turf mowed too short, and UNL sets 3 to 3.5 inches for cool-season lawns, but Arizona Extension uses frequent low mowing in spring to drain purple nutsedge tubers in bermudagrass (Arizona AZ1818). Kyllinga thrives at 1 inch or less, NC State says (TurfFiles), so low mowing helps it. Mow for the turf species first; our lawn care schedule lists heights by grass.

Which nut grass control fits your lawn?

Pick by species, then by lawn grass, then by season. Yellow nutsedge in any lawn: halosulfuron before June 21. Purple nutsedge in a warm-season lawn: a two-spray program with a halosulfuron or imazaquin label that lists your grass. Kyllinga: imazaquin on warm-season grass, because SedgeHammer rated poor on kyllinga in Tennessee trials (UT W260). Beds: dig or spot-spray glyphosate.

If your situation is	Do this	Why (source)
A few young shoots, under 5 leaves	Pull or dig them every 2 to 3 weeks through summer	No new tubers yet before 5 to 6 leaves (UC IPM)
Yellow nutsedge in a cool-season lawn, May to mid-June	Halosulfuron 0.9 g plus surfactant per 1,000 sq ft, or sulfentrazone at the label rate; repeat in 4 to 8 weeks	Before tubers start June 21 (UNL; Purdue)
Nutsedge in a St. Augustine lawn	Halosulfuron (or Image if not overseeded); skip sulfentrazone	UGA rates St. Augustine sensitive to sulfentrazone (UGA B-978)
Nutsedge in a tall fescue lawn	Halosulfuron, sulfentrazone or bentazon; never imazaquin or sulfosulfuron	Image may injure tall fescue; Certainty kills it (EPA 73342-4; EPA 59639-226)
Purple nutsedge in bermuda or zoysia, Southwest	Burndown in spring, then 2 ALS sprays about July 4 and mid-August	Arizona sequence; 2 ALS sprays a summer to slow resistance (AZ1818)
Green kyllinga mats	Imazaquin or a professional imazosulfuron or trifloxysulfuron label; fix wet spots	Rated excellent vs poor for SedgeHammer (UT W260)
Nutsedge comes back every year in the same wet spot	Fix drainage or irrigation before the next spray	Long-term control needs drainage fixed (UT W260; UC IPM)
Nutsedge in shrub or flower beds	Dig 8 to 14 in deep, or glyphosate on young plants; polypropylene fabric under mulch	Glyphosate kills what it touches; plastic does not stop leaf tips (UC IPM)
Air at or above 90°F, or drought-stressed lawn	Wait for cooler weather	Turf injury risk, especially sulfentrazone (Purdue)
You are spraying lawns for paying customers	Hold the state applicator license first	Professional products such as Certainty and Monument are not sold to homeowners (UC IPM)

1. 1Is it under 5 leaves with only a few plants?

   YesPull or dig every 2 to 3 weeks; no new tubers have formed yet (UC IPM).

   NoGo to the next question

2. 2Is it in a flower bed or shrub border?

   YesDig 8 to 14 in deep or spot-spray glyphosate on young plants; use polypropylene fabric under mulch.

   NoGo to the next question

3. 3Does it have a round green seedhead and no tubers (kyllinga)?

   YesImazaquin on warm-season grass or a professional imazosulfuron or trifloxysulfuron label; SedgeHammer rated poor.

   NoGo to the next question

4. 4Is the lawn St. Augustine?

   YesHalosulfuron (SedgeHammer) at 0.9 g per 1,000 sq ft; skip sulfentrazone, which UGA rates sensitive.

   NoGo to the next question

5. 5Is it purple nutsedge (chained tubers, purple seedhead) in warm-season turf?

   YesTwo sprays: halosulfuron or imazaquin, then again 4 to 6 weeks later; max 2 ALS sprays a summer.

   NoGo to the next question

6. 6Does the patch sit in a spot that stays wet?

   YesFix irrigation or drainage first, then spray.

   NoYellow nutsedge in a cool-season lawn: halosulfuron or sulfentrazone at the 3 to 8 leaf stage, before June 21, repeated in 4 to 8 weeks.

Source: UC IPM pn7432; UT W260; UGA B-978; Arizona AZ1818; UNL; EPA label 81880-1

Question	Short answer	Source
What is it?	A sedge, yellow (C. esculentus) or purple (C. rotundus) nutsedge	Purdue
Spread	1 tuber: 1,900 shoots and 6,900 tubers in a year	Purdue LR
Spray when	3 to 8 leaves, before June 21 (yellow)	UGA; UNL
Lawn-safe active	Halosulfuron: tolerated by all 7 grasses UGA lists	UGA
Mix	0.9 g + 2 tsp surfactant in 1 gal per 1,000 sq ft	EPA 81880-1
Repeat	4 to 8 weeks; 2 to 3 years to cut tubers 90%	Purdue

This page is general information, not pesticide-application or legal advice. Labels change and some states restrict products; read the label on the product you buy, follow it, and check your state department of agriculture’s rules before you spray or hire an applicator.