Identifying and removing weeds
Weeds are an unavoidable fact of life for gardeners. Identifying them correctly will help you tackle them early.
10.07.2023
What makes it a weed?
You may have heard it said that a weed is simply a plant growing in the wrong place – and there is some truth in this: no strict definition of what a weed is exists, and many of the plants we refer to as weeds serve as valuable wild herbs or indicator plants. So identifying them correctly is worthwhile in case you uncover a surprising benefit from your outdoor interloper.
For home gardeners, the term “weeds” describes unwanted plants that grow in the garden or the lawn. They are wild plants that are generally extremely resilient and propagate rapidly. The most familiar weeds can also withstand extremes of hot or cold weather very well, which is why it often seems nigh-on impossible to entirely kill them off. Many weeds will deposit seeds and runners that remain dormant, deep in the earth, only to germinate readily – even decades later – when brought closer to the surface by digging.
Weeds grow in two ways: they spread either by their roots or their seed. Identifying the type of weed you have means you can find out how it propagates and how best to eliminate it.
Root-spreading weeds
The hardy roots of these weeds can spread out across the bed or under the grass. Footpaths and even fencing don’t stop them: their root rhizomes are sometimes many metres long and can meander through the entire garden.
When identifying weeds, it is important to establish the root-spreading types. Shredding or mowing these weeds into small pieces does nothing to destroy them and is, in fact, likely to compound your problem by creating many more starting points from which plants can grow. The only way to get rid of these weeds once and for all is to carefully dig them out of the earth with their roots – ideally all in one piece. This kind of weeding is laborious, but it pays dividends into the future.
Seed-spreading weeds
This type of weed produces large quantities of seed, meaning it can reproduce quickly and on a wide scale. Dandelions are a classic example of a troublesome weed that spreads like this when the flower matures to become a “dandelion clock” and efficiently distributes its distinctive wind-borne seeds.
Other common seed-producing weeds include gallant soldiers, chickweed and greater celandine. These mostly annual plants reproduce across large distances, and the genetic material can survive for years or even decades in soil before germinating again when the ground is dug over. That is why weeds often spring up in freshly created beds or new lawns.
The best long-term approach for getting rid of these weeds is to weaken them through repeated hoeing and cutting. The key is to attack them before they flower, or at least before the flowers mature, as they will then have no opportunity to reproduce and so could disappear from your garden for the long term. However, be aware that some seed-propagated weeds, including dandelions, also have strong roots, and they can spring back up from root material in the ground. For these weeds, a long-term solution means dealing with the roots as well.
Do I need to get rid of weeds?
You definitely don't need to if you like them! But, because of their resilience and how rapidly they can spread, before long, weeds will compete directly with your cultivated plants and food crops, depriving them of water, nutrients and light. So, while your perennials, shrubs and ornamentals have been carefully selected to grow where conditions are right, weeds spring up wherever they like. Your chosen plants depend on the right care and environment to thrive, while weeds are less picky and find it easier to spread. They also grow more quickly, are more resilient, and can introduce diseases and attract pests. So identifying them is the first step to restoring the balance in your garden, and if addressed early, the weeds can be eliminated for good.
Identifying and tackling weeds
The better you are at accurately identifying weeds; the more targeted your approach can be. We have listed some of the most common types of weed and how to eliminate them.
Identifying weeds: field bindweed (convolvulus arvensis)
Propagation type: Root
Characteristics: Climbs up other plants by winding itself around them; found throughout the UK. An aggressive plant despite its pretty flowers.
Damage: Stunts the growth of other plants and overwhelms them.
How to tackle: Use a hoe to cut off any shoots above the ground or pull them up by hand. It takes a lot of patience to tackle this weed in the long term, as the slender rhizomes are long and difficult to remove from soil. However, if you repeatedly cut the weeds back during the gardening season, you will continuously weaken the deep roots and eventually exhaust the weed’s reserves. As it doesn’t generally spread overground, field bindweed can certainly be tolerated in secluded areas.
Benefit: No benefit.
Identifying weeds: stinging nettle (urtica urens and urtica dioica)
Propagation type: Root
Characteristics: Stinging nettles come in a small (urtica urens) and a tall variety (urtica dioica). Both produce an unpleasant stinging sensation on contact with the skin.
Damage: Propagates quickly via roots and seeds.
How to tackle: Can be cut down with a brushcutter. Afterwards, use a garden fork to loosen the earth and lift the roots to make sure the weeds don't return. Note that all stinging nettle growth within an area of around one square metre comes from a single plant.
Benefit: Home-made nettle manure and liquid fertiliser are great for strengthening crop plants and combatting pests such as greenfly. Stinging nettles also provide essential habitat for some species of butterfly, as the caterpillars of admirals, the peacock butterfly and the small tortoiseshell butterfly feed exclusively on nettles.
Identifying weeds: gallant soldiers (galinsoga parviflora)
Propagation type: Seed
Characteristics: An annual weed that prefers sunny locations, also known as potato weed. Produces yellow and white flowers and large quantities of seeds. Dies off with the first frost.
Damage: Spreads extremely quickly and can germinate the following year. Competes with other plants for light, water and nutrients.
How to tackle: Remove through regular hoeing or weeding, ideally while the weeds are still young, so they can't flower and mature.
Benefit: No benefit.
Identifying weeds: ground elder (aegopodium podagraria)
Propagation type: Root and seed
Characteristics: Persistent perennial weed producing many seeds, and with roots that can regenerate. Grows up to 80 centimetres tall. Spreads quickly and must not be composted with seeds or roots, as these will sprout in the compost. Creamy-white umbels of flowers.
Damage: Deprives other plants of nutrients and space.
How to tackle: Lift the weeds out of the soil with a digging fork to remove them.
Benefit: No benefit.
Identifying weeds: creeping buttercup (ranunculus repens)
Propagation type: Root
Characteristics: Also known as crowfoot, buttercup thrives in damp meadows and water’s-edge locations. In dry conditions, the yellow flowers may become nut fruits, but most spreading is by underground runners. Buttercups thrive in acidic soil.
Damage: Spreads extremely widely and robs other plants of space. It can be especially problematic on lawns, as it suppresses growth of grass.
How to tackle: As buttercups prefer acidic soil, the grass can be bolstered and the weed weakened by spreading lime to change the pH. Regular mowing, particularly during flowering, also prevents seed formation. Digging up is the most effective long-term approach; pulling up the roots is best, but as they are extensive it may be difficult, and can also cause holes in the lawn.
Benefit: In small doses, the buttercup may be tolerated as a guest in the garden, as the yellow flowers are a beautiful addition.
Identifying weeds: shepherd’s purse (capsella bursta-pastoris)
Propagation type: Seed
Characteristics: Produces rosettes of leaves and tiny flowers. The seeds can survive for long periods, remaining dormant for up to 30 years.
Damage: Competes with other vegetation (including grass) for nutrients. Transmits the pathogen clubroot, which attacks the roots of other plants and damages them.
How to tackle: Remove and destroy it before the seeds mature.
Benefit: No benefit.
Dandelion (taraxacum)
Propagation type: Seed
Characteristics: Yellow flowers that mature to form the familiar dandelion clock. Seeds can germinate for up to 10 years.
Damage: Spreads extremely quickly and far, thanks to wind-borne seeds. Also regenerates easily due to its strong taproot.
How to tackle: Mow the lawn, pull up the plant and deal with it before flowers mature.
Benefit: A well-known wild herb, with all parts edible.
Identifying weeds: couch grass (elymus repens)
Propagation type: Root
Characteristics: Vigorous perennial weed. Rhizomes may be as deep as 10 centimetres underground. Needs lots of light.
Damage: Suppresses other plants and grasses and damages lawns. Also occurs in perennial beds.
How to tackle: There are different ways to tackle couch grass depending on where it occurs. You can cover the affected areas with cardboard to starve the light-hungry rhizomes. This method takes some time, so you may wish to conceal the covered areas with compost. Removing the weed by hand is laborious but often successful. Another method is to plant potatoes in affected beds: the dense leaves will soon deprive the rhizomes of light.
Benefit: A pioneer plant, which means it's hardy and can grow in thin soil and barren environments where most vegetation cannot survive.
Identifying weeds: chickweed (stellaria media)
Propagation type: Seed
Characteristics: Flowers almost all year round and has small, white flowers. Annual, herbaceous plant. An internal section of the shoot is often left behind when the plant is pulled up.
Damage: Does not cause much damage but consumes a lot of nutrients and can choke out smaller plants.
How to tackle: The shallow roots are easy to pull up with the plant. You should always replant and mulch lawns and garden beds quickly after removal as a preventive measure. Because chickweed prefers soil low in nutrients, fertilising may also help.
Benefit: As a pioneer plant, it protects barren areas from erosion.
Identifying weeds: field horsetail (equisetum arvense)
Propagation type: Root
Characteristics: Field horsetail likes damp, compacted clay soil and a somewhat acidic environment.
Damage: Chokes out other plants and is difficult to weed out.
How to tackle: Improving the soil is the first step, as the weed favours typically poor conditions, thriving in compacted ground in particular. Improving aeration and preventing waterlogging will keep the weed from spreading. Cut the plant back repeatedly and add sand and compost to loosen and gradually improve the quality of the soil.
Benefit: Contains a lot of silica and can be used as a remedy for fungal diseases.
How to dispose of and destroy weeds
There are several ways to dispose of weeds. If the plant has already flowered and matured, it should not be composted, as the seeds usually survive and can germinate again later.
You should always compost weed roots with care. Start by identifying which weeds propagate via roots, and don’t add those roots to your compost. It's best to put those in your garden waste bin. For other weeds, make sure the roots are chopped up before composting; otherwise, you may simply be adding a viable plant to your compost heap.
With those caveats in mind, composting weeds is the best thing to do, as they break down to valuable nutrients that will certainly prove useful.
The best way to dispose of large volumes of weeds that can't be composted is to put them into the appropriate waste disposal at a recycling centre or a local green waste collection facility. You can dispose of smaller quantities of weeds in your domestic organic waste. This also applies to seed-propagating weeds and roots, as it will ensure that they cannot germinate or sprout again.
Bee-friendly meadows: where weeds become friends
Bear in mind that although we may find weeds unwelcome in our gardens, bees and other creatures enjoy the welcome variety they offer. The flowers of many types of weed are a good source of nectar for them, so consider leaving some of the uninvited guests in place if you can.
Summary: identifying and eliminating weeds
- Weeds are plants that spread quickly and are not wanted on the lawn or in the garden.
- Generally, there are two types - those spread by seeds or by root.
- Seed-spreading weeds should be cut back at an early stage, before seeds can be produced.
- Root-spreading weeds can spread throughout a large area by means of their root rhizome systems: an entire plant can grow from small fragments of root. The most effective way to tackle them is to pull them up and remove their roots from the soil.
- The more precisely you can identify the type of weed, the more targeted your approach can be in tackling it. Differentiating between root-propagating weeds and seed-propagating weeds is a good way to determine how to combat a weed effectively.
- You can dispose of weeds by composting them, adding them to your garden waste collection or, for larger quantities, taking them to an appropriate recycling centre or green waste collection facility.
