Best Japanese Knotweed Killers of 2025

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Last Updated - 05/07/2025

Best Choice

01
Japanese Knotweed Injector 2021 Model Now with 7 Side Hole Needles

jk injector

9.7

Exceptional

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.
02
Elixir Gardens 360 g/l Glyphosate Commercial Industrial Strength Weed Killer | Treats up to 3332 sq.m | Concentrated Herbicide/Weedkiller | 2 x 1 Litre Bottle + Measuring Cup & Gloves

Elixir Gardens

9.5 Simple to use

8.9 worth the money

8.7 Long life

Why we love it

Kills weeds at the root.

Covers large areas efficiently.

Suitable for various surfaces.
Main highlights

Super concentrated 360 gram/litre Glyphosate formula. DILUTION REQUIRED. Kills & eliminates weeds at the root.
Quickly & effectively clears areas of weeds and unwanted vegetation.
Perfect for a range of hard surfaces such as patios, decking, aggregates and driveways.
PLEASE NOTE: Depending on the type of weed and climate, please allow up to 7 days to see the effects of the treatment. Some weeds may take up to 4 weeks for the weedkiller to take effect.
IMPORTANT STOCK UPDATE: Depending on current stock levels you may receive a 2 Litre Gallup Glyphosate Bottle. This is exactly the same 360g/l glyphosate formula and is produced by the same manufacturer as Elixir Gardens Glyphosate.
2 litres treats up to 3332 sq. meters.
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9.6

Exceptional

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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Value for Money

03
Roundup Tree Stump Weedkiller, Super Concentrate 250 ml

Roundup
32% Off

9.3 Simple to use

8.4 Precision

8.4 Simple to take off

Why we love it

Effective on tough weeds and tree stumps.

No harmful residue left behind.

Includes reusable pipette for precision.
Main highlights

Liquid concentrate tree stump & root killer
Leaves no harmful residue
Kills up to 16 tree stumps
Kills stumps, trees, brambles, nettles, deep rooted woody weeds and even Japanese Knotweed
Degraded in the soil by micro organisms
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9.5

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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04
AMK® Roundup Tree Stump Killer Root Professional 250ml Liquid Concentrate Japanese Knotweed Weed

AMK

Why we love it

Effectively eliminates tough weeds.

Leaves no harmful residue.

Reusable pipette for precision.
Main highlights

Kills up to 16 tree stumps
Kills the roots so weeds don't come back
Kills ivy japanese knotweed, saplings, brambles and nettles to the root
Degraded in the soil by micro organisms, Leaves no harmful residue
Contains a reusable pipette for specialist treatment of japanese knotweed
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9.4

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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05
Weedblast Rootkill Weedkiller 2 x 2.5 Litre, Ready to use Glyphosate Weed Killer, Long Hose Trigger

Weedblast

Why we love it

Kills weeds down to the roots.

Biodegradable with low bee toxicity.

Effective in low temperatures.
Main highlights

Prevents regrowth - Long lasting effect against regrowth of tough weeds. For use on unwanted vegetation and areas not intended to bear vegetation. First signs of control, a yellowing of the leaves, may take from a few days to 2-4 weeks to appear.
Multi use - Suitable for use in gardens and on allotments, Spray plants and undersides of leaves until dripping wet.
MAPP 20049 - contains 7.2 g/L (0.72% w/w) glyphosate as a ready to use formulation
Kills weeds and roots - Ready to use spray, works against problematic weeds such as goutweed, field horsetail, moss and algae. A complete herbicide for both weeds and grasses, works down to the roots.
Biodegradable - Leaves no harmful residues to allow replanting within 7 days. Useful at low temperatures and biodegradable, low toxicity to bees.
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9.3

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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06
Rootblast | Super Strength Concentrated Total Weed Killer - Super Strength Glyphosate for Effective Weed Control - Kills Weeds down to the their roots (1 x 500ml), Packaging May Vary

Rootblast
Free Shipping

Why we love it

Effectively kills weeds at the root.

Simple to mix and apply.

Works on a wide range of weeds.
Main highlights

WHERE TO USE: For use on unwanted vegetation. DO NOT use on lawns.
SUPER STRENGTH GLYPHOSATE: With a high concentration of glyphosate, Rootblast provides effective control over a wide range of weeds, including tough-to-kill perennial weeds.
MIXING: Add 24mls of RootBlast Super Strength Total Weedkiller to 1 litre of water to treat up to 40 square metres (5m x 8m). Shake/agitate the mixture thoroughly before use. Use immediately after mixing.
KILLS WEEDS AT THE ROOT: Unlike other weed killers that only target the leaves of weeds, Rootblast penetrates deep into the soil to kill weeds at the root, preventing them from growing back.
EASY TO USE: Simply dilute Rootblast with water according to the instructions and apply to the affected areas with a sprayer for quick and easy application.
CONCENTRATED FORMULA: Rootblast weed killer is a powerful solution that comes in a concentrated form, making it highly effective at killing weeds down to the roots.
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9.2

Excellent

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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07
Roundup 119407 Fast Action Weedkiller Pump 'N Go Ready To Use Spray, 5 Litre

Roundup
Free Shipping

8.7 Simple to use

8.7 Easy to build

8.4 Long life

Why we love it

Quick visible results.

Safe for kids and pets.

Easy to use and refill.
Main highlights

The Pump N Go pressure sprayer is easily refillable, a one- touch trigger prevents hand fatique and extendable lance avoids bending.
Leaves no harmful residues to allow replanting
Kills most garden weeds with a single application; up to 10 minutes of continuous spray when using 5 L option
Item does not comes with expiry date. Note - Date printed on the item is production date
Fast action ready to use weed killer that kills the weeds and roots with visible results in 1-2 days
Degraded in the soil by micro organisms
Children and pets need not be excluded from treated areas (once dry)
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8.9

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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08
Elixir Gardens 1 Litre 360 g/l Glyphosate Commercial Industrial Strength Weed Killer | Treats up to 1666 sq.m | Concentrated Herbicide/Weedkiller

Elixir Gardens

9.5 Simple to use

8.9 worth the money

8.4 Long life

Why we love it

Effectively kills weeds at the root.

Covers large areas efficiently.

Versatile for various hard surfaces.
Main highlights

Super-concentrated 360 gram/litre Glyphosate formula. DILUTION REQUIRED. Kills & eliminates weeds at the root.
Quickly & effectively clears areas of weeds and unwanted vegetation.
Perfect for a range of hard surfaces such as patios, decking, aggregates and driveways.
PLEASE NOTE: Depending on the type of weed and climate, please allow up to 7 days to see the effects of the treatment. Some weeds may take up to 4 weeks for the weedkiller to take effect.
One 1 Litre bottle treats up to 1666 sq. meters!
IMPORTANT STOCK UPDATE: Depending on current stock levels you may receive a 1 Litre Gallup Glyphosate Bottle. This is exactly the same 360g/l glyphosate formula and is produced by the same manufacturer as Elixir Gardens Glyphosate.
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8.7

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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09
Elixir Gardens 4 Litre Deep Root Killing Glyphosate Weed Killer | 7.2g/l Herbicide & Weedkiller | Ready to Use Formula Supplied with Spray Head & Hose | 4L Bottle x 1

Elixir Gardens
10% Off

9.3 Simple to use

8.0 worth the money

8.0 Long life

Why we love it

No dilution needed, ready to use.

Covers large areas efficiently.

Includes convenient spray gun.
Main highlights

Ready-to-use 7.2 gram/litre Glyphosate formula. NO DILUTION REQUIRED. Kills & eliminates weeds at the root.
Perfect for a range of hard surfaces such as patios, decking, aggregates and driveways.
PLEASE NOTE: Depending on the type of weed and climate, please allow up to 7 days to see the effects of the treatment. Some weeds may take up to 4 weeks for the weedkiller to take effect.
One 4 litre bottle treats up to 140 sq. meters.
Effectively clears areas of weeds and unwanted vegetation. Supplied with a handy spray gun and hose attachment for easy application.
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8.6

Very Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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10
Gallup Biograde Weedkiller RTU 4L - Extra Strong Glyphosate Spray for Effective Weed Control on Driveways, Gardens, Paths & Patios, Quick Application

Gallup
Free Shipping

Why we love it

Extra strong formula ensures complete weed elimination.

Easy-to-use trigger for precise application.

Covers large areas efficiently.
Main highlights

WIDE SPECTRUM CONTROL - Effectively combats a range of weed types. Specially formulated to tackle both annual and perennial species, offering comprehensive weed management.
VERSATILE APPLICATION - Effective on various surfaces. Perfect for use on gardens, paths, patios, and driveways, delivering reliable weed control where you need it.
QUICK & EASY USE - Comes with an attachable trigger for precise spraying. Designed for straightforward application, making weed control effortless and efficient.
LARGE COVERAGE AREA - Each 4L bottle treats up to 160m², providing extensive coverage. Ideal for maintaining large areas like driveways, gardens, and more with less effort.
EXTRA STRONG FORMULA - Powered by 7.2g/l glyphosate for unparalleled weed elimination. Targets annual and deep-rooted perennials, ensuring your space stays weed-free.
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8.5

Good

Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service level, popularity, trends and more. The rankings reflect our opinion and should be a good starting point for shopping.

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