Our site is reader supported, this means we may earn a small commission when you buy through links on our site.
4 Strongest Weedkillers – Kills everything & Professional Grade
Last Updated on
We look at 4 of the strongest weedkillers that the professionals use for killing everything from hard to kill perennial weeds to tree stumps and even one weedkiller that kills everything but grass, great for using on lawns or near lawns
The strongest weedkiller available is:
After much research and testing, we think that Gallop Weedkiller which is a Glyphosate based weedkiller is probably the strongest weedkiller available for not domestic use. Its kills almost everything it comes into contact with and its readily available on Amazon.co.uk here. You can read more about it further down in the main review. Always apply in the growing season to ensure good results.
There are many weedkillers (also known as herbicides) on the market, but what do you do when the common weedkillers that have been created for home use, are simply not effective enough?
Luckily there are a few professional grade weedkillers on the market that are very effective if you know which ones they are, the good new is we do, at least 4 of them which we will share with in this post.
Most are systematic which means that the plant takes it into it’s system and it eventually kills the whole plant including the root ensuring that they do not re-grow. Thats one of the facts that makes some weedkillers very effective while other only kill the top so the weeds just simply grow back.
Industrial Glyphosate weedkiller
Most weedkillers used by professional gardeners to treat commonly used areas around buildings, large areas of beds and borders as well as on paths and car parks have one thing in common.
Most are concentrated, Glyphosate-based weedkillers which means we needed to find Glyphosate based weedkillers, the problem is some have different levels of glyphosate in so are weaker than others. However all weedkillers have to write the level of chemicals in them on the bottle so you can work out which should be the best.
Glyphosate weedkillers have many advantages, one being that it kills the foliage and the roots. Another advantage is that once the weedkiller touches the soil it bio-degrades into natural substances and does not poison the soil like some other residual weedkillers.
Glyphosate is used in some domestic weedkillers but in a much weaker concentrate, professional weedkillers are much stronger meaning they are much more effective.
They control most broad-leafed weeds as well as grasses, it is important that these weedkillers are only used when the weeds are actively growing which is usually between March and September for best results.
Triclopyr based weedkiller
Triclopyr based weedkillers are selective and will kill nearly everything but grass, we only have one recommend weedkiller that contains triclopyr and that is SBK Weedkiller. This is good for using on or near lawns an will even kill woody plants like brambles.
Recommended very strong weedkillers
There are four what we would call professional-grade weedkillers available from manufacturers and they are all available as a concentrate and need to be applied with a garden sprayer, some can be applied with a watering can but we wouldn't recommend it. It is very important that you use protective clothing especially gloves when mixing and using industrial weedkillers.
Below is our top 4 recommended professional strength weedkillers we recommend.
Gallop is probably the best selling professional strength weedkiller available for industrial use and by far the best weedkiller that can be used by the general public. While many weedkillers have been banned over the years, Gallop has somehow avoided being banned, at least for now and anyone can buy it, a quick look on Amazon.co.uk will shows that it readily available.
Always read the instruction before use, keep away from lawns and any plants you don't want to kill, this means avoid using on windy days and take care when spraying.
This systemic weedkiller is a foliar-applied translocated herbicide that can be used in aquatic areas unlike some other weedkillers available, you should however avoid contact with waterways such as rivers and ponds, a little common sense should be used here, it's deadly stuff and in the wrong quantities can damage the environment.
One mistake many people make and assume the weedkiller treatment has not worked is applying it when the weeds are not actively growing. This weedkiller like most others, needs to be applied when the weeds are actively growing as they take the poison in through the foliage, if the weeds are not actively growing such as in winter, this process will not take place and weedkillers will have very little effect.
The good news is that it will kill most annual, hard to kill perennial weeds and grasses. It will also usually kill mares tail but we recommend spraying mares tail with the tops cut off and it usually needs to be sprayed a few times to be effective and is not guaranteed.
Many people ask what can kill Japanese knotweed, the answer is usually a glyphosate-based weedkiller so this weedkiller will usually work for most people, just be prepared to spray when it returns as it can take a few years before it can be completely killed off, professional companies treat areas for around 5 years when treating large area so one spray will not have much effect, it won't work miracles.
It is available in several different quantities including a 1 litre container, a 5 litre container and a 10 litre container. It has flexible application rates but it is recommended that you mix 300ml of concentrate for every 10 litres of water (30ml to every 1 litre of water). This is only a guide and measurements can change so always read the instructions on the bottle before mixing.
Overall, Gallop 360 Weedkiller is an excellent weedkiller and is an excellent way to treat larger areas. Very effective and will kill almost all weeds, most with just one spray.
Best Weedkiller For Tree Stumps and Woody Plants
Roundup Super Concentrate Tough Weedkiller is ideal for eliminating tougher, deep-rooted weeds like brambles, thistles, nettles, and couch. This is a non-selective weedkiller so is additionally good for clearing areas such as unwanted vegetation in on paths, drives, gravel areas etc. Its well worth noting you can’t use this on the lawn unless you want to kill the grass, it you want to kill weeds on the lawn we recommend reading this post here.
Being a systemic weedkiller, the product kills tough weeds down to the roots, ensuring that they do not grow back. its worth noting that the effects start to show after 48 hours and basically, you will see yellowing of leaves and stem. However we don't recommend removing the weeds for at least 7 days to ensure the weedkiller has passed through all the roots.
What we like about about this weedkiller is it can be used on woody growth where most weedkillers cannot as they have no effect, this means it can also be used tree stumps which can handy as well as killing off woody shrubs.
The 1 litre super concentrate formula we reviewed treats a maximum area of 90m2 so gives you plenty of coverage even on fairly large areas. If the product is used for the light treatment of annual weeds, replanting and sowing can begin the next day after application which is useful, specially for those with allotments. But if applied to areas with dense cover including perennial weeds, then allow about 7 days for the systematic action to reach deep into the roots before digging or cultivating as we have already mentioned. The product is easily broken down by micro-organisms in the soil to allow replanting and the soil can actually be planted straight away as the weedkiller does become inactive as soon as it hits the soil which is useful and more environmentally friendly.
Application can be done by sprayer or a watering can that’s fitted with a very fine hose but we always recommend using a sprayer if possible as it goes a lot further.
Its advised to keep kids and pets out of treated areas until the weedkiller has dried on leaves for safety reasons and in order to avoid transfers to the lawn. And be sure to rinse the sprayer thoroughly after application, we recommend you rinse the sprayer at least 3 times.
The Resolva Xtra Tough Concentrate Weed Killer is another effective on annual and deep-rooted perennial weeds as well as broad-leaved weeds such as creeping thistle and annual sowthistle. Westland say it has enhanced killing performance because of the IQ technology which utilises the speed of a contact weedkiller plus the deep root penetration of a systemic weedkiller. Not sure this is any more advanced than most other weedkillers on our list but it does work if applied properly and at the right time of year.
Just like our previous two recommendations, this weedkiller is also biodegradable and it’s broken down in the soil by microorganisms. What we will say which is true for most weedkillers is, if it rains within around 6 to 8 hours of the weedkiller being sprayed, the effectiveness of this weedkiller can reduce significantly and you will probably need to treat the area again so check the weather forecast.
A systematic, non-selective, and non-residual weedkiller, it seeps into the foliage and travels down into the root system where it destroys the growth enzymes. As a result, it kills the weed and prevents future growth which is what helps male it so effective.
The best time to apply this weedkiller is between probably between late March and early September when the weeds are actively growing. As always, avoid application on lawns and be careful not to spray the weedkiller on areas you don't want to kill anything.
Overall this product is great for eliminating an area overridden with unwanted weeds. The scope of this weedkiller includes common nettle, cleaves, curled dock, creeping buttercup, scotch thistle, and many more. The 1 litre bottle size we reviewed has ergonomically designed with finger grips on one side to ensure a firm grasp. It’s affordable and also available in a 200ml bottle or 6 x 100ml sachets as well as the 1 litre bottle, usually the larger bottles offer better value for money.
The Best Weedkiller For Killing Everything But lawns
The Vitax SBK Brushwood Tough Weedkiller is another tough product that removes weeds without harming the surrounding vegetation and is the last on our list of the best strong weedkillers. This also kills weeds such as brambles, thistles, nettles, dock, ivy, hardwood saplings, and tree stumps.
It contains triclopyr, which is effective on woody plants and broadleaf weeds, but it does not affect grass which means its the only weedkiller on our list you can use without having to worry about killing your lawn, you could even use it on your lawn if you have lots of weeds on the lawn too, specially good for violets.
It does have a residual effect so you can expect the spray lingering around in the soil for a few weeks which means you can't really plant the area straight away. The active ingredient is biodegradable with a half-life of 60 days, but it remains active in dead vegetation for up to 90 days. As such, this weedkiller must be applied at least 6 weeks before re-cultivating or sowing.
The best time to apply on hardwood saplings and tough weeds with this weedkiller is from around May to October when the soil is moist. Woody weeds best respond to treatment from June to August, whilst tree stumps respond well between autumn and winter when the sap is retreating downwards.
Although it doesn't kill lawns, we do not recommend using on newly-turfed lawns. Lastly, this weed killer doesn’t is available at a good price and it’s available in 125ml, 250ml, 500ml bottles and q litre bottles of concentrate.
Important information when using all weedkillers.
There are a lot of weedkillers available, yet we only really recommend 4 different weedkillers. Our top recommended and probably the most effective is Gallup Glyphosate Weedkiller, its probably the strongest weedkiller available to the average person.
it kills almost everything, although notoriously hard to kill weeds such as mares tail can take several applications, because mares tail is waxy plant, it can be hard for weedkillers to penetrate, one effective pre-treatment way to improve the effectiveness is to walk through or run your hands through the mares tail to break it up a little, this seems to helps the weedkiller penetrate the plants surface as it gives opening for the weedkiller to get into the mares tail.
If you have an areas of lawn to treat or very close to a lawn or other grasses then the Vitax SBK Brushwood Tough Weedkiller is a better choice as its selective and will not kill grass.
We hope we have helped you find the best weedkillers, just remember to spray when those weeds are actively growing as no matter what weedkiller you use, its unlikely to have an effect.