Reader support helps keep the reviews honest and the site humming. As an Amazon Associate, I earn from qualifying purchases.7 Best Dallisgrass Killer | 2.5 Gallons That Finally Kill It

Check Price on Amazon

MSMA has been the industry standard for dallisgrass control in warm-season turf for decades, and this 2.5-gallon jug delivers a 48.3% concentration that is potent enough to handle heavy infestations. Mixed at 2 ounces per gallon of water, it translocates through the leaf tissue into the rhizome system, causing complete necrosis of the clump within 10–14 days. Users on Japanese zoysia report near-total eradication of dense dallisgrass patches after a single application when mixing instructions are followed precisely.

The product is restricted in several states due to its arsenic-based chemistry, and it is absolutely not safe for St. Augustine, centipede, or cool-season grasses like fescue. Overdosing is the most common mistake—excess concentration can send bermudagrass into temporary dormancy, especially during heat stress or drought. A non-ionic surfactant is strongly recommended to help the solution adhere to the waxy dallisgrass blades.

At this volume, you are buying a multi-season supply for a typical half-acre lawn. The value per application is unmatched for homeowners who maintain bermudagrass or zoysiagrass and face recurrent dallisgrass invasions. Just confirm your state’s MSMA regulations before ordering—some retailers cannot ship to certain addresses.

Check Price on Amazon

Quinclorac is the go-to selective herbicide for crabgrass and dallisgrass in cool-season lawns, and this 18.92% concentrate from Prime Source offers strong post-emergent activity. When mixed at 4 ounces per 2 gallons of water with a methylated seed oil (MSO) surfactant, users report that dallisgrass clumps begin curling within 72 hours and turn completely brown within a week. The selectivity allows it to be applied over tall fescue, perennial ryegrass, bermudagrass, and zoysia without damaging the desirable turf.

The label lists over 20 target weeds including foxtail, torpedograss, and field bindweed, making this a versatile product for lawns battling multiple grassy invaders. A surfactant is not optional—quinclorac needs it to penetrate the waxy leaf cuticle, and a blue indicator dye helps avoid skips and overlaps during spraying. Some users report needing a second application 14 days later for mature dallisgrass clumps that have developed thicker rhizomes.

This 64-ounce bottle treats a substantial area, and the concentrate stores well for spot treatments in following seasons. It is a much safer choice than MSMA for homeowners who overseed with fescue or have mixed lawns where grass species vary across the property.

Check Price on Amazon

SpeedZone EW is a four-way combination of 2,4-D, dicamba, mecoprop-p, and carfentrazone-ethyl that delivers visible weed damage within hours, not days. Clover, spurge, ground ivy, and wild violet show curling and browning in as little as 24–48 hours, and the label allows reseeding after just 7 days. While this formulation is primarily a broadleaf killer, it has proven anecdotal efficacy against dallisgrass when applied during active growth in cool weather.

The big advantage here is speed and cool-temperature performance—most herbicides stall below 60°F, but SpeedZone maintains activity down into the 50s. On dormant or semi-dormant dallisgrass clumps in early spring or late fall, this can be the tool that hits before the weed fully wakes up. The gallon bottle covers roughly 21,000 square feet, making it economical for large lawns with mixed weed populations.

This product is banned or restricted in several states including CA, CO, CT, IL, and NY due to the dicamba component, so check local laws before purchasing. It is also a contact herbicide with limited systemic movement, meaning big dallisgrass clumps may require multiple applications to reach the root crown.

Check Price on Amazon

Mesotrione (the generic equivalent of Tenacity) offers dual pre-emergent and post-emergent activity, making it one of the few herbicides that can both prevent dallisgrass germination and attack existing plants. The active ingredient inhibits carotenoid biosynthesis, causing susceptible weeds to bleach white before they die—a visual signal that the product is working. Users on centipede grass, tall fescue, and Kentucky bluegrass report safe application with no turf thinning when label rates are followed.

This 8-ounce bottle makes roughly 24 gallons of spray solution at standard rates, which is enough for multiple spot treatments on a typical suburban lot. A critical requirement: activation requires 0.15 inches of rainfall or irrigation within 10 days, otherwise the product sits on the leaf without translocating. A non-ionic surfactant and a blue dye are strongly recommended to verify coverage, especially on dense dallisgrass clumps where the waxy leaf surface can repel droplets.

Mesotrione works more slowly than MSMA or quinclorac—full death typically takes 2 to 3 weeks—and established perennial clumps may require a follow-up application. But for homeowners who want a single product that handles both pre-emergent prevention and early post-emergent control without the toxicity restrictions of MSMA, this is an excellent balanced choice.

Check Price on Amazon

This 20-ounce version of SpeedZone EW gives you the same fast-acting four-way chemistry as the gallon jug but at a lower entry point for homeowners dealing with small patches of broadleaf weeds and occasional dallisgrass. The same visible results within hours apply—spurge, clover, and dandelions curl up rapidly—and the cool-weather performance remains intact down into the 50s. It is rainfast in as little as 3 hours, which is a major advantage when unpredictable spring showers threaten to wash off a treatment.

The limitation is volume: treating a full acre with the 20-ounce bottle requires careful measurement and multiple refills of your sprayer. One user noted that the cap holds roughly 0.2 fluid ounces—useful for measuring but not explicitly marked. For spot-spraying scattered dallisgrass clumps in a small lawn, this bottle is economical and avoids storing a large jug of concentrate that might sit unused for months.

As with the gallon size, this product is not a systemic, rhizome-killing solution for heavy dallisgrass. It is best used as a component in a broader weed-management program, hitting the broadleaf competitors that stress the turf while a separate product targets the grassy dallisgrass directly.

Check Price on Amazon

Southern Ag Crossbow combines triclopyr and 2,4-D into a powerful low-volatile formulation that is primarily marketed for woody brush and perennial broadleaf weeds. Users have found it highly effective on tough vines, poison ivy, and deep-rooted perennials like creeping Charlie, and some report success on grassy weeds when applied at higher concentrations. The 1-gallon bottle makes up to 96 gallons of spray solution, giving you massive coverage for large rural properties, fence lines, or pasture edges where dallisgrass has taken hold.

The key difference from standard three-way herbicides is the triclopyr component, which provides stronger systemic activity against woody and waxy-leafed plants. However, Crossbow is non-selective on many turf grasses—it will severely damage or kill bermudagrass, fescue, and zoysia if drift occurs. This product is best used for spot-treating dallisgrass in non-turf areas like gravel driveways, sidewalk cracks, or around ornamental beds where collateral grass damage is acceptable.

The label warns against application within 3 days of rain due to extended water-phase activity, and the odor is notably strong during mixing. For homeowners who need a broad-spectrum brush killer that also hits dallisgrass in tough locations, this is a cost-effective gallon option—but it is not a lawn-friendly selective herbicide.

Check Price on Amazon

Barricade is a pre-emergent granular herbicide containing 0.48% prodiamine, designed to prevent weed seeds from germinating rather than killing existing plants. Applied in early spring and again in fall, it creates a chemical barrier in the top inch of soil that stops dallisgrass seedlings from establishing root systems. The DG Pro formulation uses a clay-based granule that shatters into smaller particles on contact with the soil, providing more uniform coverage and longer residual activity compared to standard fertilizer-herbicide blends.

This 50-pound bag covers up to 14,200 square feet, making it a practical investment for homeowners who want to blanket their lawn before weeds emerge. Users note that crabgrass pressure drops significantly after the first season, and the product remains effective for up to 8–12 weeks depending on rainfall and soil type. However, Barricade will not touch existing dallisgrass clumps—it is strictly a preventive tool that must be paired with a post-emergent killer for established patches.

The prodiamine concentration is lower than professional-grade liquid formulations (0.48% vs. 4–8% in liquids), but the granular format is easier for homeowners to apply with a standard broadcast spreader. For a long-term dallisgrass management strategy, this is the critical first step: stop new seeds from sprouting while you attack the mature clumps with a selective post-emergent.