How to kill dandelions – but why you shouldn’t

So, if you want to know how to kill dandelions, we’ve got your back. But before you reach for the weedkiller (or the lawn mower, and make one of these grass-cutting mistakes), read on and find out why you might want to at least wait until the plant has finished flowering.

These weeds are able to generously spread themselves around a garden, so if you want to know how to kill dandelions, it’s best to consider a two-pronged approach. 

We asked Boyd Douglas-Davies, of British Garden Centres, to explain the most effective ways to get rid of dandelions from a lawn, and how to stop them returning.  

“One way is to pull up the dandelions by the root, as this will not harm the grass or other plants around them,” he says. “Use a weeding knife and remove the entire main taproot. We recommend doing this when the soil is warm and moist. Dandelions have long roots, so it’s essential that these are removed to stop the plant from growing back.” 

The pronged blade of a weeding knife helps to effectively reach those long roots.  

Though some gardeners like to minimise the chemicals they use on their land, when you’re dealing with stubborn weeds it can feel like you’re left with no choice but to use weedkiller. 

If your lawn is experiencing problems with dandelions, British Garden Centres advises using a triple-action lawn fertiliser and weedkiller. This will kill weeds and their roots (check that dandelions are on the list), as well as any moss, as this can also be a problem with lawns. The fertiliser will also help to make the grass greener and more luscious.  

Remove any weed remnants and dead, blackened moss with a lawn scarifying rake. Then reseed any bare patches with grass seed. Read our guide on how to plant grass seed successfully. Your lawn should now be free of dandelions.  

If you’re just looking to kill localised dandelion flowers, British Garden Centres recommends tackling them with Weedol Rapid Weed Killer. Get the type that’s ready to use and is pet and child safe once dry.

If you really hate dandelions and are tired of relentlessly pulling them out of your lawn, then prevention is better than cure. 

“The best way to conquer dandelions long term is to have a healthy lawn,” says Peter Chaloner, managing director of Cobra Garden. “There are quick fixes to remove the immediate problem, but without changing the conditions they will most likely just come back time and time again.  

“A good lawn care regime of scarifying, aerating and mowing will prevent any dandelions and have lawns thriving.”  

If you are mowing your lawn regularly, Chaloner advises you follow the ‘one-third rule’. This means only removing one third of the grass blade height at any one time. 

“Cutting more than this weakens the plant and creates a shallow root system that will cause more problems in the future,” he adds. “Make sure you attach the grass bag as well to catch the cuttings and seeds and stop the dandelion seeds from spreading further.” 

As dandelions are less likely to call a healthy lawn their home, improving the quality of your grass is vital, and we’ve sourced some expert tips to help…

For those of you who may feel a pang of guilt, but still feel you need to kill dandelions, before you reluctantly head outside with your weeding knife, consider if they need to be removed immediately. 

“Leave dandelions to finish flowering before any mowing,” suggests Boyd Douglas-Davies of British Garden Centres. “Cherish and encourage these wonderful plants that are so important to our pollinating insects.” 

Campaigns like Plantlife’s No Mow May and Wild About Gardens (a joint effort from The Wildlife Trusts and RHS) are encouraging people to let their lawns grow longer. This is to improve the environment in your outside space for the pollinating insects needing food during the warmer months. It is also supporting the food networks and lives of other creatures visiting your patch.   

The message from Wild About Gardens in particular has been to encourage gardeners to “champion dandelions and other wildflowers by letting lawns grow longer”.  

There are 239 dandelion microspecies recorded in Britain and Ireland, according to The Wildlife Trusts, and 58 of those are endemic. This means that they are only found in the British Isles.  

Dandelions are central to garden ecosystems, supporting more than 50 different species of insects, including bees, moths, flies and wasps. Garden birds then feed on some of these insects, so of course dandelions help to establish this food chain.  

Even the fluffy seed heads of dandelions provide food for birds such as sparrows and goldfinches.  

The Wildlife Trusts says that by avoiding frequent mowing, you’re giving dandelions and other wildflowers such as daisies, selfheal (Prunella vulgaris), lesser celandine (Ficaria verna), cowslip, and bird’s-foot-trefoil (Lotus corniculatus) a chance to grow and flower, providing nectar and pollen for pollinators.  

Alison Steadman, actress and ambassador for The Wildlife Trusts, has been vocal about the importance of leaving lawns to grow long, and allowing flowers like dandelions to flourish. 

“Longer lawns offer birds the perfect foraging spots, especially when there are plenty of wildflowers in amongst the grass,” she says. “One of my favourite animals is the hedgehog. What better way to make them feel welcome than a luscious patch of grass and wildflowers to hunt for worms and beetles? I do hope you’ll join me in freeing your lawn and letting golden dandelions flourish for a splash of colour.”