How to get rid of weeds

Follow our hints and tips for a weed free garden

'No-dig' or 'lasagne' bed at Sizergh Castle, nr Kendal, Cumbria (pictured above)

Weeds can be either an absolutely frustrating annoyance or an invaluable wildlife habitat and nature’s medicine chest, depending upon your point of view. Maybe consider leaving a small patch of weeds in a shady corner to provide for the wildlife, nettles (Urtica dioica) are especially appreciated by butterflies as food for their larvae. Many herbal remedies can be made from the weeds in your garden. However if we want to grow vegetables and have a beautiful flower border then unfortunately they have to go. If you are taking over a neglected garden then I'm afraid you’re faced with a lot of hard work as they are often over-run with pernicious perennial weeds which are the hardest to get rid of, as they more often than not regenerate from even the tiniest bit of root.

If you don’t take out the weeds they will colonise any bare soil and take all the nutrients and water destined for your flowers and vegetables, resulting in poor yield and a poor display of flowers. Not only do they starve your plants but they provide a nice cool shady habitat for slugs and snails.

Weed seeds can remain dormant in the soil for years and as soon as you dig it over and bring them to the surface they will germinate so try and disturb the soil as little as possible. Vegetables can be grown in ‘no-dig’ or ‘lasagne ‘ beds and just add a compost mulch to herbaceous borders every year and the worms will incorporate it into the lower soil strata.

Recipe for 'no-dig' or 'lasagne' vegetable bed at Sizergh Castle, nr Kendal, Cumbria

Annual weeds

These are weeds which germinate from seed and die all within one year but they do self-seed prolifically so you need to take action against them otherwise your garden will be over-run as soon as the weather warms in spring.

• Mulching to a depth of 7cm (3”) will kill most annual weeds; so if you put down a thick layer of compost you can plant into the top of it. The roots will go through the rotting weeds. Don’t use a large chunky bark mulch as weeds will grow if there is even the tiniest chink of light.
• Hand weed when the ground is damp as the weeds are more likely to come out of the soil intact. A low kneeler is especially useful when weeding a border by hand as it can be back-breaking, otherwise use a hoe to save your back.
• ‘No-dig’ or ‘lasagne’ beds are a great time and labour saving option for growing vegetables and what’s more they give really good yields. You don’t dig them so you’re not disturbing the weed seeds. 
• Hoe regularly just below the soil surface and the weeds will shrivel up; this is easiest done when the ground is dry. This is the best method of weeding established beds or vegetables as you can precisely target the weeds without doing any damage to your plants.
• Try and get a good ground cover between your herbaceous plants and make sure you don’t leave huge gaps between the plants. Vinca and Cornus canadensis are good ground cover and don’t mind a bit of shade. Alchemilla mollis produces lots of leaf which blocks out the light, but it does seed everywhere so could become as big a problem as the weeds.
• Prevent weeds from setting seed; if you don’t have time to remove them at least chop off their heads before they have time to go to seed.
• A weed torch could be a good environmentally friendly option if you have a large patch of weeds. It just runs off a standard gas canister and will dry the weeds up in seconds; just don’t keep it in one place until the weeds catch fire as this could spread uncontrollably if you have a lot of tinder dry vegetation.
• Chickens will keep down weeds and you get the added bonus of lovely fresh eggs. They are ideal if you have a patch of annual weeds but they won’t make any impact on the perennial weeds. Just keep them out of the vegetable patch if you have any emerging seedlings as they don’t discriminate between veggies and weeds.
• Weed-killers should be the last option for dealing with annual weeds as there are so many other effective ways of removal; however Solabiol is an environmentally friendly weed-killer based on organic fatty acids.

Perennial weeds

This group of weeds includes brambles (Rubus fruticosus), bindweed (Convolvulus) and mare’s tail (Equisetum) which are really, really difficult to eradicate as they will grow from even the tiniest bit of root.

• Mulching to a depth of 15cm (6”) is supposed to kill them but they will first need all the top growth cut off; if you have a strimmer with a blade, not the nylon line, then it should cut off most of the growth. Any thick stems will have to be cut off at ground level with loppers. Before you spread any mulch it is advised to lay down some heavy duty weed suppressant membrane; if you don’t want to go to this expense then you can use old carpet, sheets of cardboard or thick layers of newspaper. The problem with putting down a weed suppressant layer is that you won’t be able to plant into the mulch as the roots won’t be able to penetrate. You will probably need to leave this in place for a couple of years. If you don’t want to look at a barren patch for a couple of years you could put gravel on top of the membrane and decorate with planted containers.
• Persistently cutting off the foliage will eventually weaken the plant but could take years, especially for plants with corms which get out of hand, such as Crocosmia.
• There’s always good old fashioned graft but if you have a large patch it is absolutely back breaking and weeds such as bindweed are almost impossible to eradicate as you have to get out every scrap of root.
• A dandelion weeder is invaluable if your lawn is plagued by these as it only disturbs a small amount of lawn and generally takes out the tap root. If you just want to weaken the dandelions (Taraxacum officinale) by starving them of sunlight just remove the young leaves and add them to a salad, they are full of vitamins.
• Weed-killer may have to used if you want to clear the area quickly. If you have a lot of Mare’s-tail bash it with a fork first otherwise the liquid will just run down its tough stems. If you just have the odd perennial weed you can get a glyphosate gel that is just painted onto the leaves; this ensures that no other plants are accidentally affected.

Patios, paving and gravel

• Heavy duty weed suppressant membrane is absolutely essential when laying down hard standing otherwise weeds will find their way up through cracks in the paving and will sprout everywhere in gravel. When laying paving remember to grout between the stones otherwise once a little organic matter has built up annual seeds will germinate.
• Boiling water or salt can be poured onto the weeds where there are no other plants to damage; don’t use this on your garden.
• Home-made herbicide can also be used, just mix either 50:50 vinegar and water or 2:1 white wine vinegar and salt with a little washing-up liquid added; again don’t use this on the garden.  
• Hand weed when the weather is wet if you only have a few coming through.
• Solabiol is an environmentally friendly weed-killer and can be used if the weeds are just annuals.

Disposing of weeds

• Putting weeds onto the compost heap needs to be handled with care as if the heap doesn’t get hot then the seeds won’t be destroyed and as soon as the compost is spread on the garden they will be reactivated and germinate. One way round this is once the compost has rotted down put small amounts into plastic bags and lay them out in the hot sunshine and the heat inside the bags should kill the seeds.
• Make weed soup with them; this is a method favoured by the gardener and writer Alys Fowler. She soaks the weeds in water until they start to smell then uses the liquid, diluted, to feed the garden and the sludge out of the bottom goes onto the compost heap. Perennial weeds are usually full of nutrients as their long roots reach deeper into the soil and take up nutrients usually unavailable to most plants.
• If the perennial weeds are full of seed then they can be burned or put into the gray wheelie bin, just don’t compost them.

Unfortunately weeds are part of the gardening process and despite all our best intentions they will always plague the gardener; none of them are easy to remove but the rewards of a glorious herbaceous border and lots of nutritious, tasty home-grown vegetables are well worth the effort.