Best Broadleaf Herbicide for Lawns by Grass Type

Broadleaf herbicides for lawns are formulated to kill weeds like dandelions, clover, and creeping charlie while leaving grass unharmed — but which product is actually safe depends heavily on which grass species you have, since several common broadleaf herbicides will damage warm-season lawns like St. Augustine or centipede even though they’re perfectly safe on cool-season turf. Here’s how the real products break down by lawn type.

Check your grass type before buying

This is the single most important step: several widely sold broadleaf herbicides explicitly warn against use on St. Augustinegrass, bahiagrass, bentgrass, carpetgrass, centipedegrass, and seashore paspalum. If you have one of these warm-season, sensitive grass types, you need a product specifically formulated for that — using a standard cool-season-safe herbicide can seriously damage or kill your lawn.

1. Ortho Weed B Gon Plus Crabgrass Control

A frequent top overall pick for cool-season and northern lawns, this three-herbicide blend kills over 200 grassy and broadleaf weeds — including crabgrass, dandelions, poison ivy, and ragweed — starting within a few hours and clearing most target weeds within about two weeks. It explicitly should not be used on St. Augustine, bahia, bent, carpet, centipede, or seashore paspalum grass.

Pros: broad weed coverage including crabgrass, fast initial action, widely available.
Cons: damages several warm-season/sensitive grass types — check compatibility before applying.
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2. Southern Ag 2,4-D Amine Weed Killer

Consistently recommended for southern and warm-season lawns, this 46.3% 2,4-D formula targets over 100 broadleaf weed species. It’s less effective against grassy weeds like crabgrass and may need repeated applications on deeply rooted perennial weeds, but it’s gentler on warm-season turf than many northern-formulated products.

Pros: suited to southern/warm-season lawns, targets a wide range of broadleaf species.
Cons: weaker against crabgrass and tough perennial weeds; may need multiple applications.
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3. Trimec Southern Broadleaf Herbicide

Specifically formulated for homeowners with sensitive southern turfgrasses like St. Augustine, Centipede, or Bermuda, where standard three-way blends (like regular Trimec Classic) can be too harsh. It’s the dedicated solution when you have both tough broadleaf weeds and a grass species that can’t tolerate standard formulas.

Pros: safe for St. Augustine, Centipede, and Bermuda where standard herbicides aren’t, still effective against common broadleaf weeds.
Cons: more of a specialty/niche product than a general all-purpose herbicide.
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4. Scotts Turf Builder Weed & Feed

For homeowners who’d rather combine weed control with routine fertilizing in one pass, Scotts Turf Builder Weed & Feed pairs a broadleaf herbicide with lawn fertilizer in a single granular application, watered in rather than sprayed. It’s a convenient option for a cool-season lawn maintenance routine, though like most weed-and-feed products it’s formulated for northern/cool-season grasses and carries similar warm-season grass warnings as straight broadleaf sprays.

Pros: combines weed control and fertilizing in one application, no sprayer or mixing required, convenient granular spreader application.
Cons: still carries warm-season grass restrictions; granular weed-and-feed products generally work best on actively growing weeds with dew or light moisture on the leaves.
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What to check before you buy

Beyond grass-type compatibility, check the application method: liquid concentrates and ready-to-use sprays target weeds directly and work faster on existing growth, while granular weed-and-feed products need to stick to moist weed leaves (applied to dew-covered grass or right before a light watering) and generally take longer to show results since they’re also acting as fertilizer. Temperature matters too — most broadleaf herbicides work best between 60-85°F; spraying in summer heat above 85-90°F increases the risk of grass damage even on tolerant turf, and spraying too early in cold spring weather means weeds aren’t actively growing enough to absorb the herbicide. Finally, if you’ve recently seeded or sodded a new lawn, most broadleaf herbicides require waiting until the new grass has been mowed several times (often 4+ mowings) before the first application — spraying too soon can kill or stunt new seedlings.

Frequently asked questions

What happens if I use a northern-formulated herbicide on St. Augustine grass by mistake?
Depending on the product and dose, you may see yellowing, stunted growth, or in bad cases dead patches that take a season to recover or need reseeding/resodding. If it happens, water the area well to help dilute and flush the herbicide, and avoid mowing the stressed grass short until it recovers.

Can I use a broadleaf herbicide and fertilizer on the same day?
With a combined weed-and-feed product like Scotts Turf Builder, yes — that’s the point. With a separate spray herbicide and separate fertilizer, it’s generally safer to space them a few days apart rather than stacking two lawn chemical treatments in one day.

How soon can I let kids or pets back on a treated lawn?
Check the specific product label, but most liquid broadleaf herbicides list a re-entry interval of a few hours once the spray has dried; granular weed-and-feed products typically ask you to wait until after the first watering-in and the granules are no longer visible on the surface.

Final thoughts

For a typical cool-season northern lawn (fescue, bluegrass, ryegrass), Ortho Weed B Gon’s broad coverage and fast action make it the practical default, and Scotts Turf Builder Weed & Feed is the convenient choice if you’d rather fertilize and treat weeds in one pass. For southern lawns generally, Southern Ag’s 2,4-D formula is the safer starting point, and if you specifically have St. Augustine, Centipede, or Bermuda grass, skip straight to Trimec Southern rather than risking a standard formula. When in doubt about your exact grass species’ herbicide tolerance, check your product’s label against your specific turf type before spraying the whole yard.