Garden weeds

Weeds can out-compete garden plants both by their physical growth and by taking up water and nutrients. Some may also provide a refuge for pests or diseases. However, they can be left to grow in more relaxed parts of a garden like wildflower lawns, informal borders, and garden margins. A balance can be achieved by letting them flower for pollinators and then removing seeds to prevent their spread. Some weeds look untidy in the smarter areas of a garden, while others are extremely invasive or potentially damaging and should be tackled as soon as they appear. Becoming familiar with garden weeds is key to a successful garden.

Weeds can be divided into two main groups: annuals and perennials. In this guide we identify the most common UK weeds that are encountered in gardens, and how best to tackle them, should you want to.

Perennial weeds

Perennial weeds are by far the biggest headache to the gardener as most are vigorous, long lived, and fast spreading. The best means of control is being vigilant and tackling unwanted perennials at the earliest sign of growth, and especially preventing them from setting seed. Do check your garden boundaries as weeds often make their way under the fence into your garden from neglected plots or wild land. Effective ways to combat perennials include thoroughly digging out all the roots – even tiny pieces left in the soil will form new plants – and covering the ground with light-excluding material for at least a year. Synthetic weedkillers are effective if applied properly, but are harmful to the environment.

Hedge bindweed

Hedge bindweed (Calystegia sepium) has twining stems, which are clothed with fresh green, heart-shaped leaves. In summer, large, saucer-shaped white flowers appear. Underground, you can identify hedge bindweed by its masses of pencil-thick, fast-spreading white roots – they break easily so dig them out with care. In late summer, watch out for long shoots that spread along the ground and can take root as they spread if not removed promptly.

If you can tolerate some hedge bindweed around the edges of your garden, it provides nectar-rich flowers for pollinators and is a foodplant for the convolvulus hawk-moth.

Bramble

Bramble (Rubus fruticosus) has long, thorny stems and serrated, ribbed leaves that are dark green on top and pale underneath – sometimes they turn purple in winter. From late-spring, five-petalled white flowers appear, followed by black fruits (blackberries) from July to autumn. Bramble is also known as blackberry, after its delicious juicy fruits.

Bramble is a sneaky spreader, as its long thorny stems can arch or creep from the parent plant to root wherever they touch the ground. If left untouched, bramble can form a large colony. However, in winter and early spring, these newly-rooted sections can be removed easily when pulled gently. Then, use a sharp spade to dig out the woody root of the parent plant.

Even a small bramble patch can provide a home for hedgehogs, birds and other mammals, while its flowers provide food for bees and its berries are eaten by birds. Its leaves are a foodplant for the bramble shoot moth.

Couch grass

Couch grass (Elymus repens) produces upright green grass blades that look innocuous above ground, but forms a mass of thin white roots that spread rapidly underground, with pointed tips that grow through clumps of plants. Once established, couch grass can be difficult to remove, but diligence and regular removal can control it.

Left to grow in small patches, couch grass is a foodplant for several species of butterfly, including the speckled wood.

Creeping buttercup

Creeping buttercup (Ranunculus repens) has fresh green, three-lobed leaves with serrated edges, and bright yellow buttercups that make a cheery display. While popular in wildflower meadows, creeping buttercup can be a pain in borders as it sends out runners (low-growing stems) which form roots and new plants when they touch the soil. To remove creeping buttercup dig out the main plant but also follow the runners and trace any new plants that have formed elsewhere in the border.

Creeping buttercup makes an excellent bee plant and is foodplant for the small beetle Chrysolina staphylaea, the leafhopper Eupteryx vittata and the lunar yellow underwing moth Noctua orbona.

Dandelion

Dandelion (Taraxacum officinale) is a familiar sight, bearing heads of bright yellow, composite flowers followed by round heads of grey-white seed, sometimes known as ‘dandelion clocks’, which are spread easily by wind. Rosettes of long, slender, toothed leaves, which are edible, grow from a long brittle tap root. Dandelions can be dug out of the ground but be careful not to snap the taproot, from which a new plant can grow.

Dandelion flowers provide food for a number of bees and other pollinators, and their leaves are used as a foodplant by the garden tiger moth.

Dock

Docks (Rumex spp.) produce huge rosettes of large green leaves that grow from deep roots. Docks quickly grow a long, deep tap root so digging out young, small plants saves masses of work later. Tall upright stems produce masses of seed in summer and autumn.

Docks have a range of wildlife benefits – broad-leaved dock is one of the foodplants of the small copper butterfly.

Enchanter’s nightshade

Enchanter’s nightshade (Circaea lutetiana) bears slender stems of oval to heart-shaped leaves on plants up to 60cm high, and tiny white flowers in summer. It doesn’t look invasive but it spreads quickly by means of slender white roots, which break easily and can be fiddly to remove.

Enchanter’s nightshade is used by flea beetles, sawflies and stiltbugs. Its leaves are a foodplant for several species of moth, including the elephant hawk-moth.

Ground elder

Ground elder (Aegopodium podagraria) is a ground-smothering perennial with dark green, pinnate leaves and elder-like flowers on tall stems in summer. It's an exceptionally vigorous and hard-to-eradicate weed as its thin white roots are brittle, making it difficult to remove completely. An herbaceous weed, ground elder dies back in autumn but reappears as green shoots in spring and rapidly forms a dense carpet.

Ground elder flowers are popular with pollinators.

Horsetail

Also known as mare's tail, horsetail (Equisetum arvense) forms upright stems up to 60cm high that look like little conifer trees with narrow, needle-like leaves. Horsetail is an incredibly deep-rooting weed with rhizomes that can grow several metres deep, so it’s hard to eradicate, but repeated hoeing and digging out does weaken it over time.

Horsetail is a foodplant for a number of invertebrates, including the horsetail flea beetle and the horsetail weevil.

Japanese knotweed

Japanese knotweed (Reynoutria japonica syn. Fallopia japonica) is a tall and vigorous weed that forms large clumps of tall, bamboo-like stems with purple spots that grow up to 2m tall, clothed with light green, heart-shaped leaves. Hanging clusters of creamy white flowers are produced in summer and autumn. It has incredibly strong roots that can damage buildings. While it's not illegal to grow Japanese knotweed in your garden, it's against the law to allow it to spread from your garden on to other people's property or into the wild. You can weaken growth by regularly removing its leaves or simply dig it up but check back for regrowth for up to three years, and remove any regrowth.

Japanese knotweed flowers are popular with pollinators.

Common stinging nettle

Common stinging nettle (Urtica dioica) bears stems that can grow to around 1.5 m high, bearing oval to heart-shaped, finely-toothed leaves with stinging hairs. Its roots are purplish when young and mature to yellow. They spread rapidly to form spreading clumps just beneath the soil surface. Control is easiest in spring when the first emerging nettle shoots indicate the whereabouts of the roots, which can be pulled out in long pieces when the soil is damp.

Common stinging nettle is a foodplant for a number or butterfly and moth species, including the small tortoiseshell, peacock, red admiral and mother of pearl. Its seeds provide food for birds.

Creeping thistle

Creeping thistle (Cirsium arvense), initially forms rosettes of long, jagged-edged, silvery green leaves, then develops a tall, branched stem topped with heads of pompon-like purple flowers. Both creeping thistle leaves and stems are liberally clothed with prickles. The fluffy seeds that are subsequently borne in abundance disperse on the slightest breeze. Underground, the roots spread and also grow deeply, so may take several goes to dig out completely.

Creeping thistle flowers are popular with pollinators, and its leaves are used as a foodplant by caterpillars of the painted lady butterfly.

Annual weeds

Annuals complete their life cycle within one growing season, with the fastest-growing weeds producing several generations. Annuals tend to be more of a nuisance than a major threat because of their short life span. In most areas of the UK, annuals survive winter, often hidden under leaves and plant debris, to mature and seed early in the following spring. Hoeing and hand-weeding is effective when weeds are small, ideally on a dry breezy day so the growth dies quickly once severed from the root. A weed burner can kill small annual weeds in paving, crevices, and gravel.

Annual meadow grass

Annual meadow grass has a short lifecycle, forming little tufts of slender green blades that bear fluffy seeds in as little as six to eight weeks. Left untouched, the clumps become bulkier and harder to dig out.

Annual meadow grass is used as a foodplant by several species of butterfly and moth.

Hairy bittercress

Hairy bittercress (Cardamine hirsuta) forms tiny rosettes of divided, mid to dark green leaves, and bears seeds on short stems 3-8 cm tall. It's exceptionally successful at spreading as the ripe seed capsules ‘explode’ to increase their spread – also potentially pinging into the weeders’ eyes, so wearing eye protection is recommended when removing mature bittercress.

Hairy bittercress is used as a foodplant by the garden carpet moth.

Chickweed

Chickweed (Stellaria media) forms dense mats of slender stems clothed with small, green, oval leaves, that sprawl over the ground for up to 30cm. Tiny, almost unobtrusive, star-shaped white flowers are followed by yellowish seed pods.

Chickweed flowers are popular with pollinators.

Cleavers

Cleavers (Galium aparine) also known as goosegrass or sticky Willie, forms tall, very thin, sprawling or climbing stems that can grow to around a couple of metres. The stems cling to their host, but the tiny, rounded seeds are worst as they attach to clothing or animals – a clever seed spreading tactic.

Cleavers are used as a foodplant by the humming bird hawk-moth.

Fat hen

Fat hen (Chenopodium album) is an abundant weed that loves rich soil. Toothed grey-green leaves clothe upright stems that grow to 45-60 cm tall, topped with whiteish-grey flowers. Preventing plants seeding is important as the seed has the potential to remain dormant for many years until exposed to light.

Fat hen is the foodplant of the bright-line brown-eye moth.

Groundsel

Groundsel grows to around 15-25 cm high, with branching green, sometimes purple-flushed stems and bearing little tufts of yellow flowers followed by fluffy seed heads. These look like a smaller version of dandelion seed heads and are readily wind-dispersed in the same way.

Groundsel provides nectar for pollinators and its seeds are eaten by birds such as finches and sparrows.

Herb Robert

Herb Robert is a member of the geranium family and looks attractive with rosettes of divided dark green to purple-flushed leaves that have a pungent smell when bruised, and small mauve flowers, but it does seed abundantly.

Herb Robert flowers are visited by bees and its leaves are a foodplant for many invertebrates including the barred carpet moth.

Shepherd’s purse

Shepherd’s purse forms tiny ground-hugging rosettes of green leaves and produces short stems of white flowers followed by heart-shaped seeds which spread abundantly.

Shepherd’s purse flowers are visited by pollinators and its leaves are used as a foodplant by the garden carpet moth.