Best Herbicides to Kill Johnson Grass in Lawns
Johnson grass can challenge lawn care efforts due to its aggressive spread and deep roots. The best approach combines systemic herbicides with careful application on established turf. The products below are among the most widely used by homeowners for broad-spectrum control, including Johnson grass when used as directed. Each option offers quick visible results, rainfast times, and root kill, with varying degrees of preventative benefits and application setups. Review the table for a quick snapshot before diving into detailed product sections.
| Product | Brand | Type | Notable Benefit |
|---|---|---|---|
| Roundup Weed And Grass Killer 4 With Pump N Go | Roundup | Glyphosate-based | Kills to the root; rainproof in 30 min; plant 1–30 days after |
| Compare-N-Save Glyphosate 16-Ounce Concentrate | Compare-N-Save | Glyphosate concentrate | Rainproof in 2 hours; up to 10 gallons ready-to-use spray |
| Spectracide 1 Gal Ready-to-Use Grass And Weed Killer | Spectracide | Ready-to-use | Accushot sprayer; visible results in 3 hours; replant same weekend |
| Roundup Dual Action Weed & Grass Killer Plus 4 Month Preventer | Roundup | Glyphosate + residual | 4 months prevention; rainproof in 30 min; results in 6 hours |
| Ortho WeedClear Lawn Weed Killer Ready-to-Spray | Ortho | Ready-to-spray | Kills crabgrass, dandelion, clover; safe for lawns when used as directed |
Below are five carefully selected products most relevant to Johnson grass control in home lawns. Each entry provides concise notes on how the product works, its application style, and where it shines best. This selection balances ready-to-use convenience with the flexibility of concentrates, so you can tailor your approach to your lawn size, weed pressure, and herbicide tolerance.
Roundup Weed And Grass Killer 4 With Pump N Go
Roundup Weed And Grass Killer 4 with Pump N Go is a ready-to-use option designed for ease and effectiveness around flower beds, trees, and other landscaped features. The product delivers systemic control by moving through a plant’s vascular system, killing weeds and grasses to the root. It targets broadleaf weeds and grasses such as dandelion, crabgrass, poison ivy, clover, spurge, and other common invaders. The Pump N Go sprayer reduces drift and provides precise application in hard-to-reach spots, which makes it suitable for patchwork around ornamentals.
Visible results begin within hours of application, with rainfast performance reported in as little as 30 minutes. The label also notes that you can replant flowers or ornamentals 1 to 30 days after application, depending on plant tolerance and site conditions. For best results, apply on calm days with minimal wind and follow label directions to protect desirable plants and prevent overspray.
- Kills weeds to the root
- Rainproof in about 30 minutes
- Replanting window: 1–30 days
- Broad-spectrum control for tough lawn weeds
Compare-N-Save Glyphosate 16-Ounce Concentrate
Compare-N-Save Glyphosate Concentrate provides a cost-efficient option for homeowners tackling Johnson grass over larger areas. The concentrate contains a broad spectrum of glyphosate (typically around 41%), a systemic herbicide that travels to the root to kill a wide range of weeds and grasses. It is rainproof in about two hours, enabling work after light showers or spacing tasks within a single day. When diluted according to label instructions, it yields up to 10 gallons of ready-to-use spray, which makes it a practical choice for extended borders or expansive lawns.
Because this product is a concentrate, it requires mixing with water and careful measurement of dilution. Follow the label’s recommended rates for weed size and density to avoid potential injury to desirable grasses. Wear protective gear during mixing and application, and keep children and pets away until the spray has dried.
- 41% glyphosate concentration
- Rainproof in 2 hours
- Makes up to 10 gallons of spray
- Economical for larger areas
Spectracide Ready-To-Use Grass And Weed Killer (1 Gal)
Spectracide Ready-To-Use Grass And Weed Killer offers a convenient spot-treatment option with a built-in AccuShot sprayer for extended reach and precise coverage around driveways, walkways, fences, trees, and flower beds. This product is pre-diluted for immediate use and focuses on fast, visible control of both weeds and grasses. Users report results within a few hours, and the label indicates that replanting new plants the same weekend can be feasible in treated areas, depending on site conditions and crop tolerance.
Key features include a continuous power sprayer with an extendable wand, making it easier to target hard-to-reach plants without kneeling or leaning close to the weed. The ready-to-use formulation reduces handling steps and helps ensure consistent application across small to medium-sized spaces near ornamentals and hardscape edges.
- ACCUSHOT sprayer with extendable wand
- Kills weeds and grasses; ready-to-use
- Visible results in about 3 hours
- Replanting possible the same weekend in treated areas
Roundup Dual Action Weed & Grass Killer Plus 4 Month Preventer
Roundup Dual Action Weed & Grass Killer Plus 4 Month Preventer provides a two-pronged approach: immediate weed and grass kill combined with a residual preventive action that helps deter new growth for up to four months when used as directed. The product is rainproof in roughly 30 minutes and typically shows visible results within six hours. It is designed for use on hardscapes, landscapes, cracks and crevices in driveways and sidewalks, around fences, and at the bases of established plants, shrubs, or trees, making it versatile for tough sites with Johnson grass exposure.
The dual-action formulation is particularly useful for homeowners dealing with ongoing weed pressure and those seeking longer-term control without frequent reapplication. Always follow the label guidance for safe use around ornamentals and edible plantings, and apply during favorable weather to minimize drift and unintended injury.
- Kills existing weeds and provides up to 4 months of prevention
- Rainproof in 30 minutes; results in 6 hours
- Suitable for hardscapes, cracks, and around borders
- Effective around fences and tree bases
Ortho WeedClear Lawn Weed Killer Ready-to-Spray
Ortho WeedClear Lawn Weed Killer Ready-to-Spray targets a wide range of common lawn weeds, including crabgrass, dandelion, and clover, while protecting established turf when used as directed. This product is designed for broadcast lawn treatments with one application delivering fast-acting control. It is formulated to be compatible with many lawn grasses, such as Bermudagrass, fescue, Kentucky bluegrass, ryegrass, and zoysia, provided the label directions are followed. The ready-to-spray format is convenient for homeowners who prefer a straightforward, whole-lawn approach.
The active control is designed to move through the plant system to disrupt growth and kill the targeted weeds at or near the root. Users should apply on a calm day and avoid applying to stressed or newly seeded lawns. As with all lawn herbicides, read the label for species-specific cautions and re-entry intervals to protect people, pets, and ornamentals nearby.
- Kills crabgrass, dandelion, clover, and more
- Safe for many lawn grasses when used as directed
- Fast-acting with one application
- Broadcast lawn treatment option
Buying Guide
What To Consider When Choosing A Johnson Grass Herbicide
Choose based on weed type, lawn tolerance, and site conditions. Johnson grass is a robust perennial weed, so a systemic herbicide that moves to the root is typically necessary. If you have ornamental beds or nearby shrubs, you may prefer products with targeted, lawn-safe formulations to minimize risk to desirable plants.
Form And Application
Decide between ready-to-use sprays and concentrates. Ready-to-use products offer quick, simple applications with minimal preparation, ideal for small to medium patches. Concentrates provide greater coverage and cost efficiency for larger lawns but require measuring, mixing, and a compatible sprayer. Pump-spray systems and wand-driven sprayers help with precision in tight spaces around beds and trees.
Speed Of Results And Replanting
If rapid weed kill is important, look for products that advertise visible results within hours, with replanting windows noted on the label. Some products permit replanting just a few days after application, while others require longer waits depending on the treated area and the crop you intend to plant. Always consult the label for specific replanting guidelines.
Lawn Safety And Plant Tolerance
Read the label to confirm which grasses and ornamentals are listed as tolerant. Non-selective products can injure desirable plants if misapplied. For lawns, prioritize products designed to minimize harm to turf grasses. In gardens or around trees, choose formulations that emphasize targeted control and safer drift profiles.
Coverage, Dilution, And Cost
Concentrates typically offer a lower cost per treated area but require more preparation. Ready-to-use formulations cost more per gallon but save time and reduce handling risks. Consider the size of your space and how often you treat it when weighing price versus convenience. Always calculate dilution rates and expected yield to estimate value accurately.
Residual Control And Environmental Considerations
Some products provide residual preventers that reduce new weed growth for months, while others focus on immediate kill. Consider whether you want long-lasting suppression or a strictly immediate effect. Also review environmental cautions, such as potential impact on nearby streams, pollinator exposure, and soil health as described on the label.
Comparative Snapshot
| Product | Spectrum | Form | Best Use | Notable Benefit |
|---|---|---|---|---|
| Roundup Weed And Grass Killer 4 With Pump N Go | Broad | Ready-to-use | Small to medium patches | Rapid kill; rainproof quickly; flexible replant window |
| Compare-N-Save Glyphosate 16-Ounce Concentrate | Broad | Concentrate | Large areas | Economical, high yield after dilution |
| Spectracide Ready-To-Use Grass And Weed Killer | Broad | Ready-to-use | Spot treatments | Convenient with Accushot wand |
| Roundup Dual Action Plus 4 Month Preventer | Broad plus residual | Ready-to-use | Cracks, crevices, borders | Kills now and prevents for months |
| Ortho WeedClear Lawn Ready-To-Spray | Selective for listed lawn weeds | Ready-to-spray | Entire lawn | Safe for common lawn grasses when used as directed |
Choosing the right herbicide involves balancing speed, coverage, and lawn safety. For Johnson grass, a systemic approach paired with careful site-specific application tends to yield the best long-term results. Always follow the product label for application rates, reentry intervals, and any restrictions related to nearby ornamentals, edible plants, or water sources. When in doubt, start with a smaller test patch to confirm turf tolerance before broadening treatment.