8 best weed killers to keep lawns and grass neat and tidy

Roundup is the top contender for the non-glyphosate range, leaning more heavily on a 43.1g/l pelargonic acid formula, which is chemically environmentally benign. The weeds on the Roundup patch were definitely dead and it was in the sunniest spot, so it’s a place most likely to see a weed-comeback.

There was a caterpillar hiding under the label (which fell into our test patch) that managed to survive. This solidified the brand’s new eco-friendly approach, as the formula didn’t have a long-term impact on insects like glyphosate would.

That being said, a recent study by the British Ecological Society showed a 96 per cent mortality rate for bumble bees sprayed with Roundup compared to controls and Weedol, so don’t spray bees with it. While (as the bluebells will attest) it does kill every green leaf it lands on, Roundup says that the weedkiller breaks down naturally in the soil and the area can be replanted in three days.

We were sent the big blue 3l tank, which is a bit of a fiddle because you have to attach the nozzle yourself and the instructions aren’t entirely clear (use a trowel to flick the cap off or you’ll ruin your fingernails. The nozzle, once attached, had a little hose that made it easier to get around the weeds. The active ingredient in this formula leans on 3.11 per cent (30.99g/l) pelargonic acid, which seems to do the trick but is also pretty evil to the rest of the garden.

It also kills spiders, but allegedly leaves bees alone so long as you don’t spray it on any flowers, including flowering weeds, which seems a bit of a catch 22. The result was however arguably the best in show, giving us the scorched earth effect we really were after. The leaves went yellow immediately and ten days later they weren’t just dead, they were brown mush down to the root.

Another glyphosate-free entry, the Neudorff killed everything that we sprayed it on in spite of a reasonably sparse, yet tough spot that had more shade on it and was a bit ivy and bramble heavy. It uses a mix of pelargonic acid (which is also used as food flavourings and to treat seizures) and maleic hydrazide to take out the leaves and roots respectively.

However, after a few days we noticed that some ivy had crept across the blast radius and started growing up the stick we used to mark the middle. We weren’t really sure what to make of it because the spray did kill the ivy leaves it hit from the same vine and it should be noted that this is a general weedkiller and ivy is the SAS commando of weeds.

The Weedol was also in a more paved and dandelion-heavy area with low lighting and did better than expected. After ten days there was a little green foliage underneath the dead leaves, which wasn’t great, but the bits that had taken the brunt of the spray were definitely gone and it looks like it hit the roots.

The bottle says you’ll get visible results in an hour, and it’s not wrong, but the extent of the damage is relatively limited. It sells for £3.85 at B&Q as well as most other outlets and garden centres and some supermarkets.

In spite of not having any glyphosate, the SBK absolutely slaughtered the wild bluebells that were unfortunate enough to be in the firing line along with the weeds around them, so it definitely works on all plants. The effects were notable after just an hour but after 10 days there was some foliage making a comeback beneath the top layer of dead leaves and stems. It should be noted that it, along with the Doff and Resolva, it had the sunnier and thicker areas.

SBK’s main selling point is that it claims to be the only triple-action weedkiller which travels through the weed to kill it at the root and prevent regrowth. It also claims that it doesn’t destroy grass and there is also a boxed version that we didn’t test.

The Job Done did what it said on the bottle – it got the job done pretty rapidly with a cocktail of 1.8 per cent octanoic acid and 1.2 per cent decanoic acid and a litre of the stuff will cover 10 square metres. It had visible results within hours and the weeds currently look dead enough for our satisfaction. The bottle design has had previous issues with imploding a little with use, but this wasn’t a massive problem for us. Job Done says it can be used to clear ground prior to planting or sowing vegetables, flowers or new lawns too as the acids used are non-residual.

Targeting a wide range of weeds, as well as moss and algae, it is ideal for paths and flagstones, like ours. Its sister product, Job Done Tough, while less eco-friendly, is also pretty good at rapidly killing and according to the manufacturer will stop grow-back for three months on more deep rooted weeds like brambles.

After using Doff, we had a bit of foliage making a comeback underneath, but it was in a denser area. Generally speaking it did well and held its own against the other brands. The company is using pelargonic acid instead of glyphosate so it is eco-friendlier and can handle the common pests like dandelions, dead nettle and knotgrass.

However, just because it’s not the deadliest, doesn’t mean it’s not useful. The company claims you can plant seeds or plants in the treated area as soon as the liquid has dried, whereas competitors recommend a few days, so it’s a good product to have if you’re already planting and spot a little weed in the corner of your beds.

Wilko’s version is £3 for a bottle, making it the cheapest of the bunch. It did a decent job at killing stems of some smaller weeds, but it wasn’t as obvious that it had taken effect on the leaves compared to its competition. The target area was less “hit by lightning” dead like some other products, and more “salad you’ve left in the fridge too long” wilted. The active ingredient is 60g/l of acetic acid (industrial vinegar), so it won’t do much long term harm, but it doesn’t do a lot of short term harm either. Some of the tips of leaves were still green ten days on. The Wilko killer is at least chemically simple and reasonably effective when combined with a little trowel work.

Clearly this summer weeds are back with a vengeance as Wilko’s garden weedkiller is currently out of stock – sign up for restock emails to tame your garden without causing too much damage.