So, why should weeds be removed from our gardens?
In the other posts in this weed control series, I’ve written about what weeds are and made the point that, fundamentally, weeds are like any other plant in the garden. So, if that is the case, why do we need to get rid of weeds?
If weeds are just plants growing in the wrong place, why should we care? Why should we bother with weeding? Is there any reason that the presence of weeds should matter to us other than that we don’t like the look of them where they are?
Of course it will depend upon what you are trying to achieve in your garden, but there are a number of reasons why the presence of weeds is likely to be undesirable and why it is important to remove weeds.
Reason to get rid of weeds 1: competition
Probably the biggest problem with weeds in the garden environment is that they compete with the plants that you are trying to grow. Just take a look at the picture at the top of this post to see what effect that can have.
Unfortunately, when it comes to a fight, there is usually only one winner. Your garden species of plants – ornamentals or edibles – have probably been bred to favour certain genetic characteristics, such as flower colour or taste.
Whilst they would not have survived as garden worthy plants without an ability to fend for themselves in your beds and borders, their survival kit is no match for that of many of the weeds they may have to compete with.
So, in particular, when you are growing for a purpose, such as to provide food for your table or cut flowers for your vase, you will need to be very watchful of competition from weeds. Weeds in a polytunnel or in your vegetable beds, for example, can quickly threaten your crops if left unchecked.
As we will see in the next post, weeds have usually invested all their evolutionary capital in ensuring their survival, whether as individual plants or as a species.
Their consequent adaptions include vigorous root systems that easily overpower those of cultivated plants when it comes to taking in available nutrients and water and an ability to grow quickly upwards and outwards so as to crowd out their neighbours and to take all the available light.
This leaves your cherished plants weakened, so that they will die off or be more susceptible to attack from pests and diseases.
In summary, therefore, it is important to remove weeds because they provide damaging competition for your chosen plants in the following ways:
- Weeds grow tall quickly. They therefore block light from your plants, affecting the plants ability to photosynthesise effectively;
- Weeds often grow vigorous root systems. Because weeds locate themselves in the spaces between plants, their roots systems crowd out the roots from your chosen plants.
- Some weeds, such as quackgrass, nutsedge, and ragweed, are able to exude toxins that inhibit the growth of neighbouring plants. This is called Allelopathy.
- With their vigorous root systems, weeds inevitably deprive your chosen plants of some (usually a lot) of the available water and nutrients in the soil. Obviously that this can be damaging for your plants and prevents them from thriving.
Getting rid of weeds will therefore reduce competition for light, nutrients, water and space and allow your plants to grow on unhindered.
Reason to get rid of weeds 2: pests and diseases
Not content with weakening your plants and opening them up to attack from pests and diseases, weeds can also be the source of those pests and diseases.
Uncleared weeds can often provide a place for pests to overwinter, whilst the lush weed canopy provides sheltered conditions to suit many pests, such as slugs and snails.
What’s more, since many weeds are adapted to germinate and/or to begin growing early in the season, thus gaining an advantage over the plants around them, their new growth can provide sustenance for sap sucking insects, like aphids. This enables colonies of sap-suckers to build up ready to attack your plants in force when they tentatively unfurl their soft spring foliage.
Weeds in the same family as cultivated plants can also harbour diseases that are specific to that family. So, for example, Shepherd’s Purse, from the brassica family may be host to clubroot disease which can decimate your cabbage family crops.
Reason to get rid of weeds 3: harvesting
This is obviously an issue with edible crops, but clearly the job of harvesting low growing leafy crops is made more difficult if weeds are mixed in and whilst some, like chickweed are edible, not all are.
So, harvesting leaves and other crops which are covered or surrounded by weeds can mean you have to spend a lot of time looking for the crops you are trying to harvest and sorting the good from the bad.
Reason to get rid of weeds 4: they can be ugly
Finally, and this may be the main reason why most gardeners want to rid themselves of their weeds, plants in the wrong place can look plain ugly, especially in a formal or highly designed garden setting.
Weeds tend to be wild, disorderly plants that clash with the orderly, maintained look of a purposefully planted garden. Their growth habits are erratic and their irregular shapes and heights stand out in stark contrast to the uniform, tidy and designed appearance of flowers, vegetables, and other intentionally sown crops. Visually, weeds can create a chaotic, unkempt look that disrupts the calm beauty of a well-tended garden.
However, it is worth acknowledging that sometimes it is not a bad idea to leave some parts of your garden unkempt and susceptible to colonisation by weeds. This is because these are the kinds of spaces that provide a have for wildlife that can bring a balance to your garden’s ecosystem and encourage the insects that you need to visit your garden to pollinate your plants.
Weed control resources
You’ll find more resources to help you learn about weeds generally and, in particular, about getting rid of weeds here:
The Gardening Step by Step weed control series
- Part 1 – What are weeds?
- Part 2 – Why get rid of weeds? – this post
- Part 3 – How weeds grow and thrive
- Part 4 – Removing weeds: the complete guide
- Part 5 – The weeding resource guide
Martin Cole has been an avid gardener for more than 20 years and loves to talk and write about gardening. In 2006 he was a finalist in the BBC Gardener of the Year competition. He is a member of the National dahlia Society.
He previously lived in London and Sydney, Australia, where he took a diploma course in Horticultural studies and is now based in North Berwick in Scotland. He founded GardeningStepbyStep.com in 2012. The website is aimed at everybody who has been bitten by the gardening bug and wants to know more.
Gardening Step by Step has been cited by Thompson and Morgan, the UK’s largest mail order plant retailer, as a website that publishes expert gardening content.
Check out my comprehensive step by step guide, with plain language explanations and ultra-useful images and illustrations. This is for you if you love dahlias and want to the best out of the dahlias you grow.