How to kill weeds
Tips on how to keep your outdoor space free from weeds
Dealing with weeds is an important part of caring for your garden. If left unchecked, they can quickly overwhelm, disfigure or kill your plants – rapidly undoing all your hard work.
By knowing how to spot, as well as control weeds, you’ll be able to help your other plants thrive. So let's get started with removing those unwanted weeds.
Weeds are simply plants that are in the wrong place. They take space, water, sunlight and nutrients from the ones we really want to grow.
There are four types of weeds:
1. Annual weeds
These weeds grow and set seed in as little as a month in summer. They only last one season, but leave seeds that will grow the following year. Prevent this by removing them before they develop seed heads and they won’t come back.
2. Perennial or deep-rooted weeds
These weeds spread invasively through their roots, and will return year after year unless fully removed – even the smallest piece of root can lead to them returning.
3. Woody weeds
These develop a strong, woody stem.
4. Lawn weeds
These need a particular weed killer otherwise it’ll kill the grass around it.
To get rid of weeds effectively, you need to recognise which ones are invading your garden. Here are eight common varieties:
This is a perennial, fast-growing climber that can smother everything in its path.
Digging it up works to some extent, but each bit of root left in the soil will grow a new plant. Stop it growing back again with repeat applications of systemic weed killer.
This perennial is easy to dig out, as its roots are fairly shallow. The big problem is its ability to spread in all directions by sending out runners - just as strawberry plants do. If you leave it unchecked, it can rapidly ruin your lawn, so use a selective lawn weed killer to stop this from happening.
Don't let dandelions get to the seed head stage, as the fluffy 'clocks' blow everywhere. Dig out the long tap root of these perennials or use a systemic weed killer (or a selective variety if they are growing on your lawn).
This is a moisture-loving perennial with jointed stems and small scale-like leaves. It's rarely found in cultivated ground, but the roots are too deep to dig out - so if it does appear, use repeat applications of weed killer until it dies down. If you spot it in your lawn, regular mowing will eventually kill it off.
You can try digging out this highly invasive perennial - but any bits of root left behind will regenerate. Constantly removing the top growth will weaken it dramatically. Treat with a systemic weed killer - although you'll need to put on repeat applications.
This perennial springs up quickly in empty spaces. As its roots are fairly shallow, you can pull them out by hand (wear tough gloves for the stinging kind), but a dense mat of roots will need treating with a systemic weed killer.
This annual looks a bit like ragwort and acts as a secondary host to many fungal rusts. Its lightweight, downy seed heads enable it to spread very rapidly. Your best bet is to pull or hoe it out, dig it out or spray large patches with a contact weed killer.
This annual has white flowers for most of the year. The explosive seed pods shoot out seeds at the slightest touch, which means it can spread very rapidly. Try pulling, hoeing or digging it out before the seed pods appear.
Start by watching our great video guide about problem weeds.
How to remove weeds by hand
There are a number of different ways to remove unwanted weeds without using weed killer.
Remove weeds with a weeding tool
Specially designed to target weeds, weeding tools make light work of blitzing those unwanted visitors. Options include weed pullers (pictured) which are ideal for lawn areas, as they sink into the turf and yank up the targeted weed. And weeders or weeding knives, which help scrape out weeds from any cracks and gaps in patios, paved areas and driveways.
Remove weeds with a garden hand tool
How to kill weeds with weed killer
If you have weeds that are proving resilient, returning regularly or are difficult to remove, you may want to use a weed killer. Make sure that you choose an appropriate weed killer for the best results. There are a few different types to look for, let's explore the options.
- Systemic weed killer
Systemic weed killers are absorbed by the foliage of the weed and carried down to the roots. As they're non-residual, you can use them to clear an area ready for planting.
But be patient - they can take up to two weeks to work. Make sure you apply them carefully, as they're non-selective and will kill any plant they touch.
- Selective weed killer
Generally used on lawns, selective weed killers target specific plants while leaving others unharmed.
- Residual weed killer
Ideal for clearing weeds in paths and patios, these leave a non-permanent residue in the soil to prevent any re-growth. They're non-selective, so make sure you use them carefully.
- Contact weed killer
These only kill the part of the plant that's above ground. While they offer fast-acting results, they don't affect the root and so the weed is still likely to return.
Because of this, we recommend opting for a more long-term solution such as a systemic or residual weed killer.
Top tip: Help the weed killer work quickly
Bruise the leaves of perennial weeds before spraying on weed killer. This helps the leaves absorb the chemicals (especially with waxy leaves like horsetail).
When using weed killer, it's important to carefully follow the instructions on the packaging.
- Store pesticides away from children and pets.
- Ensure all container lids are secure.
- Always follow the manufacturers instructions for use of pesticides.
- After use, children and pets should be kept away from the treated area until the treatment has dried.
- Never use pesticides near any edible plants, such as fruit and vegetables.
- Never store garden chemicals in unmarked containers and don't buy more than you need for one year.
- Wear gardening gloves when treating weeds, and thoroughly wash hands after use.
- Spray early in the morning or late evening when bees are not active.
- It is illegal to put any garden chemical down a main drain or waste water drainage system, even when diluted.
- Ask your local council for advice on disposal of unwanted pesticides or empty containers.
How to dispose of weeds
Once the weeds are removed from the ground, collect them all in a work cart, small wheelbarrow or strong garden tub to make it easier to transport them for disposal. And remember not to add them to your compost. Instead, throw them away or burn them.
Once you've cleared the area of weeds, make sure they don't come back by taking preventative action.
Lay weed control fabric
Weed control fabric allows water, air and nutrients to penetrate through into the soil but keeps weeds in check. Cut into strips and lay between plants if looking to maintain some planting, or use in larger amounts if there are no plants to consider.
Reduce the likelihood of weeds taking hold by mulching your beds and borders in spring or after planting. Mulch is layers of organic material, such as compost or bark, that once spread onto soil can provide a barrier to stop weeds popping up. It also locks in moisture and can look attractive too.