The fight between gardeners and weeds has been long fought, but in a hurry to remove these unwanted plants, mistakes can be made. The young leaves of the dreaded green alkanet can look an awful lot like your prized foxgloves, and while pulling out swathes of speedwell it would be easy to grab up precious new shoots of honesty.
Identifying the real weeds early in the season is the key to having a worry-free growing season, allowing you to remove the ones you don’t want in your garden before they establish and take over your borders, but leaving the special things you do want to nurture.
Here’s our handy guide to the most common garden weeds so you can target the right ones when you head out with your trowel in hand.
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10 common garden weeds to spot
Green alkanet
Green alkanet (Pentaglottis sempervirens) is a perennial plant that thrives in partial shade but will grow in a wide variety of conditions. Introduced originally as a garden plant, it has small blue flowers in spring and as well as those foxglove-like leaves, with these pretty blooms it could easily be confused with forget me nots or shade-loving Brunnera.
Green alkanet is seen as a particularly annoying weed as it can spread quickly by self-seeding and form patches in the garden that could smother smaller plants. Due to its deep tap root, it can be hard to remove once it gets a hold in garden borders.
It can be difficult to identify green alkanet early in the season as its leaves can easily be mistaken for foxgloves, comfrey, pulmonaria or other plants in the borage family. To be sure what you have is green alkanet, look for rosettes of oval leaves that sometimes have white speckles on them. If you are still unsure, you can wait for the plant to grow upwards and produce its mauve-pink buds or pretty blue flowers on hairy stems.
Control: An effective way to stop the spread of green alkanet is dead-heading before the plants set seed and by removing small plants as they appear, being sure to dig out the root. The flowers of green alkanet are edible and can be used as a decorative garnish in salads, so when removing flowers to control spread you could save them to use in the kitchen.
If you have a wild garden and a looser approach to gardening, however, it is worth knowing that green alkanet can be beneficial to a wide range of garden wildlife. The flowers are nectar-rich for pollinators and the leaves provide food for scarlet tiger moth larvae. The large clumps of wide leaves provide great groundcover and hiding places for other invertebrates.
Bindweed
There are two main types of bindweed – field bindweed (Convolvulus arvensis) and hedge bindweed (Calystegia sepium). Hedge bindweed is the most problematic in gardens as the stems can reach up to 3m long, trailing across the ground or usually twining their way up the stems of tall plants. The pale roots, easily snapped, can reach down to 4m deep, so it can be very hard to remove them all, and they will regrow quickly from the tiniest segment.
Field bindweed is less problematic than hedge bindweed and only usually affects country gardens bordered by farmland. Its trailing or twining stems don’t often extend beyond 1m.
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Both types of bindweed are native wildflowers in the UK. The funnel-shaped flowers support a wide range of pollinators and the leaves of hedge bindweed provide food for beetles and several types of moth, including convolvulus hawk-moth and elephant hawk-moth.
Some naturalistic gardeners such as the late Henk Gerritsen have tried to rehabilitate its reputation as a thug by training it to grow up obelisks and supports like a normal garden climber, but even then it would not do as it was hoped, draping itself across the hedge behind instead.
Control: To remove bindweed, you have to dig out the roots as deeply as you can using a weeder, hori hori or even a spade and carefully trace the root down as far as you can in order to remove as much as possible; then cover the regrowth area with deep mulch, cardboard or a weed membrane if you can.
It can be tough to spot bindweed early, but look out for the twining skinny stems with heart shaped leaves emerging fresh and green in spring and autumn, and dig them out with the whole root as soon as you spot them.
Couch grass
This fast-growing grass, Elymus repens, looks very similar to the grass growing in your lawn (and may well be growing there too) but this is more vigorous, produces a dense mat of rhizomes and has blades that can reach around 40cm tall.
Couch grass comes into growth very early in spring, and you may notice tufts of it in flowerbeds (especially those edged by lawns), bare soil and cracks in paving. It spreads via rhizomes and via seeds.
Although seen as the scourge of allotmenteers and previously neglected ground, it is an important food source for butterfly and moth caterpillars, including those of speckled wood and ringlet butterflies. If growing in a species-rich lawn or meadow, couch grass can be considered an attractive plant worth retaining in the garden.
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Control: Couch grass can be differentiated from lawn grass, which has fibrous roots, by its white underground rhizomes that creep and spread easily. Dig out couch grass to remove it from areas where it is not wanted, making sure to bring up as much root as possible. Regular mowing will easily suppress its growth in lawns. You can also smother it using a layer of cardboard topped with 20cm of mulch.
Creeping buttercup
The pretty, bright yellow flowers of creeping buttercup (Ranunculus repens) are great for pollinators and look great growing in a wildflower meadow or area of long grass. However, it does have a tendency to spread via runners and roots and can be unwelcome in some parts of the garden such as borders and flower beds.
To identify creeping buttercup early, look out for leaves that are divided into three deeply lobed leaflets with serrated edges. The leaves sometimes have pale markings and small, pale hairs cover both the leaves and stems.
Control: In a lawn, frequent mowing should keep it under control. Keep the lawn well aerated, and rake before mowing to lift out the runners as well as deadheading the flowers before they set seed. In a border, pull out plants, taking care to remove as much of the root system as possible – our editor recommends Sneeboer’s Wrotter as a great tool for this task. You can also try cutting them right down and smothering them with cardboard and a 20cm layer of mulch.
Speedwell
There are actually four species of speedwell that can be spotted in gardens. They are all low-growing plants with pretty blue flowers. They can provide nectar for solitary bees, and are a food plant for heath fritillary butterfly.
Speedwells thrive in manicured lawns and in borders, although they rarely cause a threat to other plants. The stems readily root along their length and can form dense patches. All four species of speedwell can be spotted early in gardens as flowers start appearing from March and April onwards. This is the easiest way to identify speedwells.
Control: In borders, small emerging plants can be easily removed by hand. It can be harder to remove patches in the lawn, as mowing will spread stems that can re-root. However, speedwell does not compete well with healthy and vigorous grasses, so adjusting lawn maintenance early in the season to promote healthy growth can bring speedwell in check.
Willowherb
The tall pink spikes of willowherbs such as rosebay willowherb (Chamaenerion angustifolium) have nectar-rich flowers and leaves that are a food source for the giant hawk moth as well as other invertebrates; they can look very attractive in a naturalistic border.
They are easy to pull out early if they are becoming a problem; or deadhead before they have set seed. However, if left unattended they can create large patches in country gardens and easily take over large parts of borders, spreading with underground shoots and rhizomes and prolifically self-seeding.
Identifying which willowherb you have in your garden can be difficult; there are many species and hybridization often occurs. But early in the season, leaves of different willowherbs can look quite different from one another. Rosebay willowherb produces low rosettes of narrow, willow-like leaves. Great willowherb and hoary willowherb also produce lance-shaped leaves, whereas other varieties have more oval-shaped leaves.
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Control: Shallow root systems mean willowherbs can easily be pulled out of borders, but the earlier you can remove them the easier it will be. If you are happy to have some in your garden, deadheading is a good way to control their spread, before they have a chance to set seed.
Ground elder
Ground elder (Aegopodium podagraria) is an invasive weed that quickly forms a dense mat of roots and a carpet of leaves. It's particularly problematic in borders as its roots can creep between and into the rootballs of other plants, making it hard to remove, and it will soon outcompete smaller or less vigorous plants. It can also make it difficult to plant new plants.
Numerous beetles, leaf miners, butterflies and moths feed on ground elder, including rare swallowtail butterflies. In wilder parts of the garden, you could consider allowing it to grow to attract wildlife and provide shelter and groundcover.
Ground elder is also edible, so when removing it from your garden you could consider using it in the kitchen – young leaves can be used like salad and older leaves as a leafy veg similar to spinach.
In areas where it will outcompete your garden plants, however, catching it before it grows too big makes all the difference. To identify ground elder early, look out for hollow leaf stalks bearing fresh green leaflets in spring. Underground, a shallow rhizomatous root system forms, with pale cream-coloured roots forming a dense mat.
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Control: Try pulling off or cutting the stems – if this is done repeatedly, it will weaken the plants. You could try digging out the roots, but take care not to damage other plants (a hori hori knife is useful for this) and to dig out as much root as possible so that it can’t regrow.
If this weed is really established, you could try digging up all of the plants from the border, dig out as much ground elder as possible and replant. This is a good job for winter, when many perennials are dormant. You can also try smothering plants, covering with a compostable material such as cardboard, or with a weed membrane.
Ground elder is another weed capable of re-growing from only small pieces of root, which makes it hard to eradicate. Make sure you don’t compost the pulled out weeds and roots in your home compost bin, as otherwise you may unwittingly spread them back around the garden.
Creeping cinquefoil
Creeping cinquefoil is a low-growing perennial with creeping stems producing bright yellow, five-petalled flowers from June to September. The flowers provide nectar for bees and the leaves are a good food source for caterpillars, including those of yellow shell moths and grizzled skipper butterflies.
It is seen as a weed but it is also a good groundcover plant that is a useful addition green roofs and wildflower lawns. The runners can also help to stabilise soil and reduce erosion, making it particularly useful in sloping gardens.
Creeping cinquefoil produces dark, thin taproots that can grow 30cm down into the soil, and new plants are able to grow from sections of taproot or detached runners, making control more difficult. It can also spread by seed.
To identify creeping cinquefoil early, look out for the stems that bear leaves made up of five leaflets with serrated edges.
Control: Use a border fork to lift out clumps, inserting it deep enough to get the entire taproot out. Hand tools designed for deep-rooted weeds are useful for targeting taproots and limiting soil disturbance. Remove small, recently rooted sections along runners with a hand fork. You can also smother the plants with a layer of cardboard and mulch.
Groundsel
Groundsel (Senecio vulgaris) is an annual weed that spreads prolifically using fluffy seed heads. It has long, lobed and ragged leaves that are stalked low down the stem, but unstalked further up the stem. The stems branch to clusters of small, yellow flower heads that look like green and yellow tubes.
The flowers are a source of nectar to pollinators and the leaves are a source of food for some moth caterpillars. Some species of birds and rabbits also eat the leaves.
Catching groundsel in your garden early is key to limiting its spread, as once it goes to seed it will start popping up everywhere.
Control: Regularly hoeing where seedlings pop up will prevent the plants from flowering and going to seed. Consistently keeping on top of groundsel will be key if you want to remove it from parts of your garden.
Horsetail
A relic from the age of the dinosaurs, this perennial weed is astonishingly resilient. Its rhizomes can penetrate more than 2m into the soil, enabling it to resurface even after determined digging. Horsetail (Equisetum arvense) quickly forms dense carpets, outcompeting other plants and even pushing up through tarmac and paving. It spreads vigorously via rhizomes as well as via spores.
Horsetail is easy to spot early in the season due to its unusual growth. Shoots appear in early to mid-spring; these early shoots are curious-looking, light tawny brown, about 30cm tall, and easily mistaken for toadstools.
It may be every gardener’s nightmare but it is worth noting that horsetail provides shelter and a food source to invertebrates.
Control: Pull or cut off new growth as soon as it appears - over time, this will weaken the plants. You can also try forking out the rhizomes, making sure no trace is left behind; do not put these on your compost heap but add to the council green waste bin instead.
You could also try smothering plants with a compostable material such as cardboard, then layering a deep layer of mulch (such as garden compost) on top. In lawns, frequent mowing can weaken horsetail over time, though it rarely eradicates it.
What is a weed anyway?
What constitutes a weed is subjective – most of these plants are strong-growing survivors or wildflowers perfectly suited to the conditions in your garden.
If you think a plant looks nice or is providing shelter and food for wildlife, there is no reason that you need to remove it. Consider leaving parts of your garden more wild if you do decide to remove a lot of weeds from your borders.
And a final reminder - where possible, avoid putting plant material from weeding into your compost heap and put it into the council green waste bins instead. Otherwise, you risk spreading these weeds further around your garden.
