Broadleaf weeds like clover, dandelion, and creeping Charlie don’t just ruin the uniform look of a lawn—they compete with turf for water and nutrients. A post emergent selective herbicide targets these invaders without harming the grass, making it the most precise tool in lawn care.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. For this guide, I compared active ingredient profiles, application rates, turf tolerances, and hundreds of owner reports across seven leading formulas to isolate the best performers for different weed pressures.
Whether you manage a residential lawn or a commercial turf site, choosing the right post emergent selective herbicide comes down to matching the active ingredient stack to the specific weed spectrum and grass type in your yard.
How To Choose The Best Post Emergent Selective Herbicide
A selective herbicide is only as valuable as its active ingredient combination. The right mix kills the weeds you have while leaving your turf type completely unharmed. Here are the three criteria that separate an effective formula from a wasted spray session.
Active Ingredient Stack Depth
Single-active formulas work on a narrow weed range. A four-way blend—like 2,4-D, Dicamba, Triclopyr, and Sulfentrazone—covers broadleaf staples (dandelion, clover, ground ivy) plus tough targets like wild violet and Virginia buttonweed. The more active ingredients in the tank, the less likely resistant weed biotypes survive the application.
Turfgrass Tolerance Spectrum
Cool-season grasses like tall fescue and Kentucky bluegrass tolerate most selective herbicides, but warm-season types like St. Augustine and centipedegrass are sensitive to certain chemistries. Always cross-reference the label tolerance list with your lawn type. A misapplied product that kills the grass along with the weed is worse than no spray at all.
Application Rate and Surfactant Use
The concentration measured in ounces per thousand square feet directly impacts speed and thoroughness. Adding a non-ionic surfactant helps the herbicide penetrate waxy or hairy weed leaves—this is especially critical for products like Quinclorac that require surface wetting to activate. Without surfactant, you may see only partial kill on stubborn weeds like crabgrass or yellow nutsedge.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Select Source Triad TZ | 4-Way Blend | Tough broadleaf weeds in turf | 2,4-D / Dicamba / Triclopyr / Sulfentrazone | Amazon |
| Nufarm Change Up | 3-Way Blend | Warm-season turf safety | MCPA / Fluroxypyr / Dicamba | Amazon |
| Syngenta Tenacity | Mesotrione | Pre/post crabgrass + seeding | Mesotrione 40% | Amazon |
| Primesource Quinclorac 1.5L | Quinclorac | Crabgrass and grassy weed control | Quinclorac 18.92% | Amazon |
| Select Source Quinclorac 75 | Dry Formulation | Long-term crabgrass suppression | Quinclorac 75% | Amazon |
| Southern Ag Crossbow | Brush + Broadleaf | Heavy brush and woody weeds | Triclopyr / 2,4-D | Amazon |
| Target 6 Plus MSMA | MSMA | Dallisgrass and nutsedge | MSMA 48.3% | Amazon |
In‑Depth Reviews
1. Select Source Triad TZ (4-Way Combination Herbicide)
The Triad TZ packs four active ingredients—2,4-D, Dicamba, Triclopyr, and Sulfentrazone—into a single quart that targets the widest spectrum of broadleaf weeds in this comparison. Owner data shows it eliminated dandelions, clover, and ground ivy within days, with complete weed death occurring in one to four weeks depending on temperature and weed maturity. The inclusion of Sulfentrazone gives it an edge on yellow nutsedge suppression that three-way blends lack.
At a cost of roughly -18 per 6,000 square feet per application, this is a high-value formula for anyone managing cool-season lawns like bluegrass, fescue, or ryegrass. Users reported visible shriveling of spurge within eight hours of mixing with a non-ionic surfactant. The product is labeled for residential lawns, athletic fields, golf courses, and commercial sod production, giving it unusually broad site approval.
The main drawback is the strong chemical odor during mixing and application, which several reviewers mentioned as a reason to wear a respirator. A small number of shipments arrived with leaking bottle seals, so inspecting the container on delivery is advised. For the most demanding broadleaf problems, especially wild violet and Virginia buttonweed, this is the most complete ready-to-mix option available.
What works
- Four-way active stack covers resistant broadleaf weeds that single formulas miss
- Rapid visual wilting within hours of application on sensitive weed species
- Versatile site labeling from residential lawns to commercial turf properties
What doesn’t
- Strong odor requires ventilation and protective gear during mixing
- Occasional bottle leakage reported during shipping
- Requires surfactant for optimal performance on waxy-leaf weeds
2. Nufarm Change Up Premium Selective Herbicide
Change Up brings a three-way combination of MCPA, Fluroxypyr, and Dicamba to tackle over 200 broadleaf weed species, and its label tolerance includes warm-season grasses like St. Augustine, centipedegrass, and zoysia—a group that many selective herbicides exclude. Users in western Kentucky reported that heavy clover infestations died within a week, and the grass underneath recovered fully without yellowing or stunting.
The application rate range of 0.46 to 1.1 ounces per thousand square feet allows fine-tuning based on weed maturity and density. Fluroxypyr is particularly effective on hard-to-kill species like oxalis and chickweed, and the Dicamba component adds punch against thistles and plantain. Several users who follow professional turf management channels cited Change Up as a top recommendation specifically for warm-season grass regions.
One limitation is that this product works through leaf absorption, so mowing immediately before application reduces effectiveness significantly—the herbicide needs leaf area to translocate to the root system. A few users noted that visible results take about a week, which is slower than some four-way blends. If your lawn is warm-season and you need a product that won’t cause browning, this is the safest premium choice.
What works
- Labeled for sensitive warm-season turf including St. Augustine and centipedegrass
- Broad weed spectrum covers more than 200 broadleaf species
- Flexible dosing allows adjustment based on infestation severity
What doesn’t
- Slow visible results compared to four-active formulations
- Requires leaf surface to be intact; mowing before application reduces efficacy
- Higher per-ounce cost than some multi-active competitors
3. Syngenta Tenacity Turf Herbicide
Tenacity is unique in the selective herbicide market because it works both as a pre-emergent and post-emergent, and it is one of the only products that can be applied at the time of seeding without damaging new grass. The active ingredient Mesotrione at 40% disrupts photosynthesis, causing susceptible weeds to turn white before they die—a visual confirmation that owners rely on to know the product is working.
User reports on nimblewill and bentgrass control show 85-90% reduction after two to three applications with a surfactant in late June through August. The whitening effect occurs within three to four days, and complete browning follows over several weeks. Homeowners with large lots valued the economy: one user treated a 0.7-acre infestation using only about one-third of the 8-ounce bottle.
The shelf life of five to eight years when stored properly makes this a good product to have on hand for spot treatments. However, the required multiple applications for tough weeds like nimblewill and bentgrass increase total time investment. Some cool-season grass species show minor temporary whitening at higher rates, so careful measuring is critical. If your strategy includes overseeding and concurrent weed control, this is the only product that reliably delivers both.
What works
- Safe to apply during seeding without harming new turf germination
- Dual pre-emergent and post-emergent activity in a single application
- Visual whitening effect confirms weed absorption within days
What doesn’t
- Requires multiple applications for tough weeds like nimblewill and bentgrass
- High concentration requires precise measuring to avoid turf damage
- Whitening of desirable grass can occur at over-label rates
4. Primesource Quinclorac 1.5L Liquid Crabgrass Killer
When crabgrass is the primary enemy, Quinclorac 1.5L delivers targeted post-emergent control that leaves desirable turf intact. Owners reported crabgrass death within three days when mixed with MSO surfactant and blue dye for coverage tracking. The 18.92% Quinclorac concentration in a 64-ounce container provides enough volume for multiple seasons of spot treatment on large lawns.
Beyond crabgrass, this formulation controls foxtail, kikuyugrass, torpedograss, and a range of broadleaf weeds including dollarweed and morningglory. One user who failed with hose-end Spectracide saw complete crabgrass elimination after a single application with Quinclorac and surfactant. The liquid formulation mixes easily in backpack sprayers, and the blue dye helps prevent wasteful overlapping.
Performance on broadleaf weeds is weaker than dedicated broadleaf blends—this product is best used as a targeted grassy weed tool rather than a general-purpose solution. A reviewer treating half an acre noted only 70% crabgrass kill, suggesting that heavy infestations may require a follow-up application. For homeowners with crabgrass pressure but minimal broadleaf issues, this is the most reliable liquid option.
What works
- Rapid crabgrass death visible within three days with surfactant
- Large 64-ounce container provides excellent value for multiple seasons
- Controls grassy weeds like foxtail and torpedograss that broadleaf herbicides miss
What doesn’t
- Weaker on broadleaf weeds compared to dedicated broadleaf formulations
- Heavy infestations may require more than one application for full control
- Mixing with MSO surfactant adds an extra purchase and step
5. Select Source Quinclorac 75 Herbicide (1 lb)
The dry formulation of Quinclorac at 75% concentration gives the highest active ingredient density in this lineup, making one pound last for many seasons of spot treatments. Owners mixing 1 tablespoon per gallon of water saw crabgrass and witch grass die within three days without damaging Bermuda grass. The dry format also avoids the leaking issues that occasionally affect liquid containers during shipping.
A notable application for this product is controlling invading St. Augustine grass in tall fescue lawns—a scenario where most selective herbicides fail because both are turfgrasses. Users in Southern California reported that Quinclorac 75 killed the St. Augustine while leaving the fescue unharmed. The maximum mix rate is 0.367 ounce per gallon, which equals about 1.4 teaspoons, so measuring accuracy is essential.
The label instructions are written in units more familiar to commercial applicators (pounds per acre), which confuses many residential users who prefer teaspoons per gallon. Some reviewers reported needing to look up conversion charts online before mixing. If you are comfortable with dry concentrates and want the longest shelf life and highest concentration per dollar, this is the right pick.
What works
- Highest Quinclorac concentration at 75% for long-lasting supply
- Effective on invading St. Augustine grass in fescue lawns
- Dry formulation eliminates risk of liquid leakage during shipping
What doesn’t
- Label directions use commercial units that confuse residential users
- Requires precise measuring with teaspoons to avoid turf damage
- Surfactant strongly recommended but not included
6. Southern Ag Crossbow Specialty Herbicide (Gallon)
Crossbow combines Triclopyr and 2,4-D in a formulation designed specifically for woody brush, vines, and perennial broadleaf weeds that standard lawn herbicides cannot suppress. The one-gallon container makes up to 96 gallons of spray solution, covering up to 2.23 acres, which positions it as the right choice for large properties with fence lines, overgrown areas, or mixed brush invasions.
Users in Ohio reported 85% kill rates on brown soil conditions, with ivy, vines, 8-foot weeds, and small trees dead within one week after a 2-ounce flow rate application. The three-day soil half-life makes it safer for the surrounding environment compared to persistent herbicides like glyphosate, and it contains no neonicotinoids. It works well on creeping Charlie and ragweed but struggles with wild violets.
Effectiveness varies noticeably by soil type—rich, organic soil reduces performance compared to leaner soils. The strong odor during mixing is comparable to industrial solvents, and rubber gloves are mandatory. Because it is not selective for all turf types, it is best applied as a spot treatment or in non-turf areas rather than broadcast over a lawn. For heavy brush and woody weed control, Crossbow is the most economical gallon option.
What works
- Excellent on woody brush, vines, ivy, and small trees where lawn herbicides fail
- Makes up to 96 gallons of spray solution from a single gallon container
- Short three-day soil half-life reduces environmental persistence
What doesn’t
- Effectiveness drops significantly on rich organic soils
- Strong industrial odor requires protective gear during mixing
- Not safe for broadcast application on most turfgrass types
7. Target 6 Plus MSMA 48.2% Turf Herbicide (2.5 Gallon)
MSMA at 48.3% concentration is the industry standard for controlling dallisgrass and nutsedge in warm-season turf like zoysia and Bermuda grass. This 2.5-gallon jug contains 320 fluid ounces of concentrated product, and owners reported that one purchase lasted over five years even with regular spot applications. The mixing rate is straightforward at 2 ounces per gallon of water for general applications.
Users with Japanese zoysia lawns heavily infected with dallisgrass saw impressive knockdown results, with the herbicide selectively removing the grassy weed while the zoysia recovered. The product is also labeled for cotton, golf courses, sod farms, and highway rights-of-way, indicating it meets professional-grade standards. A reviewer noted that the formula is thick and of visibly higher quality compared to consumer-grade products.
Over-mixing or applying in hot weather can stress Bermuda grass into temporary dormancy, and one owner who used 1.25 tablespoons per 2 gallons saw browning of the desired turf that required a full season to recover. MSMA is also more restricted than other selective herbicides; some states limit its use to commercial applicators only. If dallisgrass is your primary target and you have warm-season turf, this is the most potent solution available—but it demands careful handling.
What works
- Most effective selective option for dallisgrass and nutsedge control
- Concentrated 2.5-gallon jug lasts multiple seasons even with regular use
- Professional-grade quality suited for golf courses and sod farms
What doesn’t
- Over-application can stress and brown desirable warm-season turf
- Some states restrict MSMA to licensed commercial applicators
- Heavy container size makes handling and measuring less convenient
Hardware & Specs Guide
Active Ingredient Stack
The number and type of active ingredients determine both the weed spectrum coverage and the speed of control. Four-way blends like 2,4-D/Dicamba/Triclopyr/Sulfentrazone cover resistant broadleaf weeds and offer nutsedge suppression. Three-way blends with MCPA/Fluroxypyr/Dicamba are safer on warm-season turf but slower on tough perennials. Single-active products like Quinclorac or Mesotrione excel on specific weed categories but require complementary products for full-spectrum control.
Surfactant Compatibility
Non-ionic surfactant (NIS) and methylated seed oil (MSO) are not just optional additives—they are often the difference between a complete kill and a partial kill. Surfactants reduce the surface tension of spray droplets, allowing the herbicide to spread evenly and penetrate waxy or hairy leaf cuticles. For Quinclorac products, MSO surfactant is nearly mandatory for crabgrass control. Most labels recommend adding surfactant at 0.25% to 0.5% of the total spray volume.
FAQ
Can I use a post emergent selective herbicide on St. Augustine grass?
How long does it take for selective herbicide to kill weeds completely?
Can I reseed after applying post emergent selective herbicide?
Final Thoughts: The Verdict
For most gardeners, the post emergent selective herbicide winner is the Select Source Triad TZ because its four-way blend covers the broadest weed spectrum while matching price per application that beats premium competitors. If you need warm-season turf safety, grab the Nufarm Change Up. And for targeting crabgrass and dallisgrass without harming Bermuda, nothing beats the Primesource Quinclorac 1.5L.