Weed Control
Dollarweed: The Weed That Tells You About Your Water
UF calls dollarweed a reliable indicator of wet environments. Clemson's first control step is not a herbicide — it is checking how often you irrigate.
Selective Pre- and Post-Emergent Herbicide (concentrate, warm-season turf)
Southern Ag Atrazine St. Augustine Weed Killer, 32 oz Review
★★★★☆ 4/5
our editor rating how we score4.3/5 from 1,158 shoppers at Amazon — their number, not ours.
$14–$19
Typical price · 32 oz concentrate; rate per label
Affiliate links — see our disclosure. Commissions never influence verdicts.
The mainstay herbicide for St. Augustine and centipede lawns, and the one whose availability depends on which state you live in.
Our Verdict
On St. Augustine and centipedegrass this is the workhorse, and there is no close homeowner substitute — it works both as a pre-emergent and on weeds already up, and those two grasses tolerate it where they will not tolerate much else. That is why it appears repeatedly in Southern lawn guidance and why 1,158 people have rated it. Three cautions belong on the front of this record rather than the back. Atrazine is regulated more tightly than most homeowner herbicides and is restricted or prohibited in some states — check your own state's rules before ordering, because a legal product in Georgia is not automatically legal where you are. It is a documented groundwater contaminant, which is the reason for those rules, so it does not belong near a well, a ditch or a storm drain; if you are on a private well, read our well-water guide first. And the turf list is narrow: this is for St. Augustine and centipede, and applying it to a cool-season lawn or to bermuda outside label directions damages the grass. Used inside those limits it is cheap, effective and hard to replace.
✅ Pros
- Works pre- and post-emergence, so one product covers weeds up and weeds coming
- Tolerated by St. Augustine and centipede, which resist most other selective options
- Around $16 for 32 oz — the cheapest effective route on these two grasses
- 1,158 Amazon ratings
⚠️ Cons
- Restricted or prohibited in some states — verify your own rules before buying
- A documented groundwater contaminant; keep it away from wells, ditches and storm drains
- St. Augustine and centipede only — not a cool-season or general-purpose lawn product
- Repeat use on the same ground is exactly the pattern the regulations exist to limit
Product type
Selective Pre- and Post-Emergent Herbicide (concentrate, warm-season turf)
Active ingredient
Atrazine
Price range
$14–$19
Coverage
32 oz concentrate; rate per label
Best for
Weed control on established St. Augustine or centipedegrass, where your state permits atrazine
our editor rating
4 out of 5
Where our facts come from
Label read on the registrant's own PDF
EPA Reg. No. 19713-567-829
We read the printed label published by the company that holds the registration. EPA hosts no PDF for this one, so this is the best available text.
What we found when we read it
Label read 2026-08-02 on the distributor's own site. EPA Reg. No. 19713-567-829, EPA Est. No. 829-FL-1 — a three-part distributor number: base registration 19713-567 packed and distributed by Southern Agricultural Insecticides (company 829). Atrazine 4.00%. Turf sites are centipedegrass and St. Augustinegrass, which is exactly why this product cannot be recommended for corn or any other crop however well atrazine performs there — the sites list is closed. Label also states 'Not for use in the states of Alaska or Hawaii', neither of which is in our 21-state set, and 'Do not use on muck or alkaline soils'.
Where this page and the container disagree, the container wins — the label is the legal authority on rates and restrictions. How to read one yourself.
Where This Product Matters
Matched against each state's actual disease, weed and pest pressure.
Alabama
Alabama hub →Dollarweed (pennywort) on wet coastal groundAnnual bluegrass (Poa annua)
🌾 Centipede🌾 St. Augustine
Application window: April–May and September, and check every label against centipede before it leaves the shelf
Alaska
Alaska hub →Common chickweedWhite cloverAnnual bluegrass (Poa annua) in compacted, wet groundChickweed and other cool-wet-condition annuals in the Southeast
Application window: June through July, inside the same short window everything else happens in. There is no autumn second chance
Arizona
Arizona hub →Annual bluegrass (Poa annua) in winter rye
🌾 St. Augustine
Application window: March–May and during monsoon flushes; Celsius-type products handle 100°F+ windows
Arkansas
Arkansas hub →HenbitAnnual bluegrass (Poa annua)
🌾 St. Augustine🌾 Centipede
Application window: Bounded by the label's temperature ceiling rather than the calendar — spring treatments finish before the June heat arrives, and nothing selective goes down again until September cools off
California
California hub →Annual bluegrass (Poa annua)
🌾 St. Augustine
Application window: March–May while weeds are young; avoid spraying drought-stressed turf in summer
Colorado
Colorado hub →White cloverClover and Banks grass mites (dry winters and hot dry summers)
Application window: May–June and September; high-altitude sun makes stressed turf easy to injure, so spot-treat rather than blanket-spray
Connecticut
Connecticut hub →White clover
Application window: Broadleaf sprays in May–June and again in September, when the weeds are moving sugars to the roots; skip July and August, when a stressed cool-season lawn takes the injury and the weed does not
Delaware
Delaware hub →Annual bluegrass (Poa annua)White clover
Application window: April to late May, then September into October. Skip July and August entirely: this is the transition zone, and a stressed tall fescue lawn takes the injury the weed shrugs off
Florida
Florida hub →Dollarweed (pennywort)
🌾 St. Augustine🌾 Centipede
Application window: March–May and October–November; avoid applications above 85°F
Georgia
Georgia hub →Annual bluegrass (Poa annua)
🌾 Centipede🌾 St. Augustine
Application window: April to early June and September–October; avoid mid-summer sprays on stressed turf
Hawaii
Hawaii hub →Dollarweed on over-watered turf
🌾 St. Augustine🌾 Centipede
Application window: Year-round where the turf is actively growing, which is most of the time; the constraint is heat and drought stress on the leeward side rather than a dormant season
Idaho
Idaho hub →Annual bluegrass (Poa annua) in irrigated, closely mown turfWhite clover
Application window: Late April into June, then September into October; skip the July and early August heat, which is also when UI's own fertilizer schedule goes quiet
Illinois
Illinois hub →Annual bluegrass (Poa annua)
Application window: May–June and September; fall beats creeping charlie best
Indiana
Indiana hub →White clover
Application window: October is the most effective month for broadleaf weeds; never apply above 80°F or to drought-stressed turf
Iowa
Iowa hub →White cloverAnnual bluegrass (Poa annua)
Application window: October, and October is most of it — but check the wind and the date against what is happening in the fields, because early-summer growth-regulator drift is a real seasonal risk here and your own spray carries the same way
Kansas
Kansas hub →Henbit and other winter annuals, which own an eastern Kansas lawn in March
Application window: April into May and again in September–October; avoid July and August, when a tall fescue lawn here is already at its limit
Kentucky
Kentucky hub →Annual bluegrass (Poa annua)Henbit
Application window: April–May and September–October; autumn is the knockout window for the wild garlic that defines a Kentucky winter lawn
Louisiana
Louisiana hub →Dollarweed (pennywort)Annual bluegrass
🌾 St. Augustine
Application window: March–May and October–November; avoid applications above 85°F and never on drought-stressed St. Augustine
Maine
Maine hub →White cloverCommon chickweed
Application window: June, then a narrow late-August to mid-September window. Maine's usable autumn is the shortest in New England
Maryland
Maryland hub →White clover
Application window: April–May and September–October; autumn is the knockout window for the ground ivy and violet the Piedmont is full of
Massachusetts
Massachusetts hub →White cloverAnnual bluegrass (Poa annua)
Application window: A narrow autumn is the real window here: late September into October, after the summer heat and before New England's early frost closes the season
Michigan
Michigan hub →White cloverAnnual bluegrass
Application window: May–June and September; autumn is the stronger window for perennial broadleaf weeds
Mississippi
Mississippi hub →Dollarweed (pennywort) wherever drainage is poorAnnual bluegrass (Poa annua)
🌾 Centipede🌾 St. Augustine
Application window: April–May and September, avoiding the midsummer heat restrictions on most labels
Missouri
Missouri hub →HenbitWhite clover
Application window: April–May and September–October; skip summer sprays on drought-stressed fescue
Montana
Montana hub →White clover
Application window: June, then late August into September. In a sub-100-day valley there is no third chance
Nebraska
Nebraska hub →Henbit and other winter annualsWhite clover
Application window: Late spring and again from late August through September, when perennial broadleaf weeds are moving reserves to the root
Nevada
Nevada hub →Annual bluegrass (Poa annua)
Application window: March–April and October in the south; May and September in the north
New Hampshire
New Hampshire hub →White cloverCommon chickweed
Application window: Late May into June, then late August through September. The autumn window closes earlier here than anywhere else in southern New England
New Jersey
New Jersey hub →White clover
Application window: May and September–October; autumn is the knockout window for perennial broadleaf weeds
New Mexico
New Mexico hub →Annual bluegrass (Poa annua) in over-irrigated cool-season turf
Application window: Spring and early autumn; in the south skip the June heat entirely, and in the north the usable autumn window closes by early October
New York
New York hub →White clover
Application window: May and September–October; autumn is the knockout window for perennial broadleaf weeds
North Carolina
North Carolina hub →Annual bluegrass (Poa annua)HenbitWhite clover
🌾 Centipede
Application window: April–May and September–October; avoid spraying heat-stressed fescue in July–August
North Dakota
North Dakota hub →White clover
Application window: Early to mid-June, then late August into early September. There is no third opportunity
Ohio
Ohio hub →White clover
Application window: May–June and September; fall applications hit dandelion taproots hardest
Oklahoma
Oklahoma hub →HenbitAnnual bluegrass (Poa annua)
Application window: Judged by wind before season: sustained wind is Oklahoma's normal condition, so the usable spray days are calm mornings in April, May and September rather than whole months
Oregon
Oregon hub →Annual bluegrass (Poa annua)
Application window: March–May and September–October; the long mild shoulder seasons give more usable spray days than most states get
Pennsylvania
Pennsylvania hub →White clover
Application window: May and September — fall is the knockout window for perennial broadleaf weeds
Rhode Island
Rhode Island hub →White clover
Application window: Broadleaf work in May–June and again in September; the September pass is the one that holds, because the weed is moving reserves down
South Carolina
South Carolina hub →Annual bluegrassDollarweed
🌾 St. Augustine
Application window: April–May and September–October, and never above 90°F — centipedegrass is sensitive to 2,4-D both at spring green-up and in summer heat
South Dakota
South Dakota hub →White clover
Application window: Early to mid-June, then late August into September, which is the pass that actually holds on perennial broadleaf weeds
Tennessee
Tennessee hub →Annual bluegrass (Poa annua)Henbit
Application window: April–May and September–October; skip sprays on drought-stressed summer fescue
Texas
Texas hub →Henbit
🌾 St. Augustine
Application window: April–early June and September–October; avoid herbicides above 90°F
Utah
Utah hub →Annual bluegrass (Poa annua)
Application window: May and September, avoiding the intense midsummer heat on the label
Vermont
Vermont hub →White cloverCommon chickweed
Application window: Late May through June, then a short late-August to mid-September window. Vermont's autumn window is the narrowest in New England
Virginia
Virginia hub →White clover
Application window: April–May and September–October; skip sprays on heat-stressed fescue in July and August
Washington
Washington hub →Annual bluegrassWhite clover
Application window: April–May and September–October; WSU caps applications at 80°F, stricter than the 85–90°F ceilings used elsewhere
West Virginia
West Virginia hub →White clover
Application window: April into May and again in September–October. Skip July and August: this is transition-zone country and a heat-stressed tall fescue lawn absorbs the injury the weed does not
Wisconsin
Wisconsin hub →White clover
Application window: Early to mid-fall is the favourable window for dandelion and other perennial broadleaf weeds
Wyoming
Wyoming hub →White clover
Application window: June, then late August into September. UW's own framing is useful: a slow-release application covers a 90 to 100 day growing season, which is roughly the entire Wyoming season
Common questions
Common Questions
How much does Southern Ag Atrazine St. Augustine Weed Killer, 32 oz cost?
Southern Ag Atrazine St. Augustine Weed Killer, 32 oz typically runs $14–$19, covering 32 oz concentrate; rate per label.
What does Southern Ag Atrazine St. Augustine Weed Killer, 32 oz treat?
Southern Ag Atrazine St. Augustine Weed Killer, 32 oz targets annual bluegrass, chickweed, henbit, dollarweed, clover.
What is the active ingredient in Southern Ag Atrazine St. Augustine Weed Killer, 32 oz?
Atrazine, registered under EPA Reg. No. 19713-567-829.
What is the biggest downside of Southern Ag Atrazine St. Augustine Weed Killer, 32 oz?
Restricted or prohibited in some states — verify your own rules before buying
Real feedback
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