Are these NIGHTMARE weeds lurking in your garden? Here's what to do, says garden writer Hazel Sillver

Weeds. They’re as much a part of gardening as flowers, fruit and veg, but that doesn’t mean you have to love them. If you’re struggling to keep ahead of them this year in your garden, here’s our rundown of nine of the rowdiest uninvited guests – and what you need to know.

1: Dandelion (Taraxacum officinale)

How it spreads: With hundreds of devilishly airborne seeds – and tricky, fragile tap-roots.

Should we leave dandelions for wildlife? Yes and no. Whilst dandelions offer nectar for bees, they are fecund weeds that can create a headache. An established clump could produce 12,000 seeds in one year if the plants are not deadheaded after flowering.

How else can I help bees? Grow non-maddening plants that bloom at roughly the same time, such as lungwort.

Why are dandelions hard to kill? Their long tap roots are hard to excavate in one piece. If you don't dig down deep enough, the dreaded snap sounds as you yank out the plant; even if the root piece left in the soil is only an inch long, it can produce new dandelions. After they've flowered, the clocks (seedheads) distribute a cloud of seed when the wind blows.

2: Running bamboo (Phyllostachys spp.)

How it spreads: Via rhizomes that run and run.

Is bamboo a weed? Some types can become weeds if not contained by a root barrier. The ones to avoid, or at least be careful with, are the 'running' forms, including those from the genus Phyllostachys. Whilst they produce beautiful culms (canes), over time, some species (such as Phyllostachys bissetii) can cause as much havoc as Japanese knotweed.

Which bamboo is best to grow? The clumping (non-spreading) forms (such as those from the genus Fargesia) are excellent, providing a low-maintenance mass of rustling evergreen leaves and architectural canes, without becoming invasive.

Why is running bamboo hard to kill? Because once it reaches maturity (which could take a decade), it produces long, vigorous underground rhizomes that can appear several metres from the parent plant, sending up new culms, which can pierce driveways and even foundations. Sections of rhizome left in the ground can form new plants. Its vigour depends on conditions: in cold regions and poor, dry soil, running bamboo often behaves itself. In warm, wet conditions, get ready for a battle.

3: Stinging nettle (Urtica dioica)

How it spreads: Spreading roots and stems, above and below the soil.

Should we leave nettles for wildlife? Yes and no. Many butterflies – including red admiral and comma – rely on stinging nettles in a sunny spot as food plants for their caterpillars, but nettles are rampant weeds that coat the ground at speed. Nettles are harmful to dogs if eaten.

How can I provide nettles for butterflies? The best approach is usually to remove nettles where you don’t want them – wear gloves and other protective clothing – but leave a big corner where they can thrive in the sun, and deliver all those wonderful wildlife benefits.

Why are nettles hard to kill? Because they colonise large areas (especially moist, rich earth in full sun) via horizontal rooting stems and spreading underground rhizomes, as well as seed. Although they don't grow deep, they can regenerate from a small section of rhizome left in the ground.

4: Creeping thistle (Cirsium arvense)

How it spreads: Wind-blown seeds, and creeping roots and stems.

Is it best to leave thistles for wildlife? That depends on the thistle. Creeping thistle is a nectar source for bees and butterflies, while birds eat the seeds and use the soft thistledown to line their nests. But it's so vigorous that it's listed in the UK's Weeds Act 1959 (which protects agricultural land) and considered seriously invasive in the USA, Canada and New Zealand, so think twice about courting it in your garden.

Are all thistles invasive? No. Prickle-free Cirsium rivulare 'Atropurpureum', with its wine-magenta blooms that bumblebees love, is superb in UK gardens. In the USA, opt for native thistles Cirsium pumilum and Cirsium discolor.

Why is creeping thistle hard to kill? Its roots and rhizomes spread fast and deep underground and re-shoot from small pieces left in the soil. The seedheads (each one composed of up to 200 seeds), scooped up by the wind, become thistledown that can travel great distances.

5: Couch grass (Elymus repens)

How it spreads: Underground stems

What does couch grass look like? It sends up flat, soft-green blades that can reach 40cm, from pale sheaths. Also known as twitch grass in the UK or quack grass in the USA, it's fast-growing and produces tall flower spikes in summer.

Is couch grass good for wildlife? Yes, it's great for moths and butterflies, but confining it to a wild patch of garden is wise.

Why is couch grass hard to kill? Its pale rhizomes creep through the soil, knitting around the roots of other plants. Pieces of rhizome left in the ground can form new plants, and the seed is capable of remaining viable underground for years.

Weeds must! Five effective ways to remove or kill weeds

1 Block out the sun by placing pieces of old carpet, cardboard or landscape fabric over the weeds for several months. Starving pernicious weeds of light is the easiest, most eco-sound way to kill them.

2 A flame gun is a quick, simple way to kill weeds in patios, driveways, and anywhere that they're not in close proximity to other plants. But bear in mind that these will only kill what’s above ground.

3 Prevention is best for an easy life. Keep an eye out for weed seedlings and remove them with a hoe or fork. Also consider covering the soil with groundcover plants or a mulch of wood chips.

4 Manual removal is arduous, but if perennial weeds have taken hold in a flower border it may be the only real option. Weeds often coil themselves around the roots of other plants, so – where possible (for instance, with perennials) – lift your ornamentals to tease out the weeds, and then thoroughly dig over to remove all traces of the weed. Keep an eye out for new growth the following year, since most weeds can regenerate from pieces of rhizome left in the soil.

5 Weedkiller should be avoided in general to protect wildlife. However, in some cases (such as the presence of Japanese knotweed), chemical treatment (usually glyphosate-based weedkiller) may be necessary. In situations such as this, it’s almost always time to call in the professionals.

6: Japanese knotweed (Reynoutria japonica)

How it spreads: Rhizomes

What does Japanese knotweed look like? An invasive non-native plant in the UK and US, this aggressive perennial has head-height, bamboo-like stems with red-purple speckling, shovel-shaped green leaves, and white tassel flowers.

Why is Japanese knotweed so hard to kill? It grows at a crazed pace, in all sorts of conditions, and regenerates from small sections of rhizome in the ground, which can grow to 14m long. It can take over waterways, bust through hard surfaces (including asphalt), and prevent little else from growing, so its presence can make a property sale difficult.

7: Horsetail (Equisetum arvense)

Spreading methods: Spores and rhizomes

Isn't horsetail a useful herb? Whilst this fascinating plant, which is native to most of the Northern Hemisphere and pre-dates dinosaurs, has been employed for centuries in herbal remedies to treat various conditions, it is a thuggish weed.

Which herb can I use for tea instead? Lemon verbena (Aloysia citrodora) is a shrubby garden herb for sun, providing a mass of sherbet-scented leaves. It has long been valued as an anti-inflammatory and can be brewed into a delicious infusion.

Why is horsetail so hard to kill? Its extensive network of long, dark rhizomes and tubers stretch deep underground, particularly in moist, open earth in full sun. A 10cm fragment left in the soil can grow into 64 metres of branching rhizome in just one year.

8: Bindweed (Calystegia sepium & Convolvulus arvensis)

Type: Climbing and trailing perennials

How it spreads: Rhizomatous roots

Don't the beautiful flowers of bindweed justify its place? Although the blooms are pretty and provide nectar for pollinators, bindweeds can be hellish to deal with in gardens. In the UK, hedge bindweed (Calystegia sepium) is the main culprit, whilst field bindweed (Convolvulus arvensis) is more of a problem for USA gardeners. Both use other plants as a climbing frame, smothering them in a veil of leaves, so they can't photosynthesise well or flower abundantly.

How else can I help pollinators? Honeysuckle (Lonicera periclymenum) is a non-invasive European native hedgerow climber, which fills the garden with scent and provides food, shelter and nest sites for moths, birds and small mammals.

Why is bindweed hard to kill? The long, pale serpentine roots spread with gusto, knitting themselves around the roots of other plants, and can regenerate from a nugget of rhizome left in the ground.

9: Ground elder (Aegopodium podagraria)

Type: Perennial

How it spreads: Rhizomes

Isn't ground elder useful for ground cover in shade? Although it forms a green carpet of elder-like leaves, even in shade, and produces wildlife-friendly white flowers, it's a ferocious weed that can quickly take over borders.

What else can I use as ground cover? Dusky cranesbill (Geranium phaeum) produces a mat of leaves in shade, as well as nectar-rich flowers for pollinators, without being nightmarishly invasive.

Why is ground elder hard to kill? Although not as torturous to remove as some weeds, since its (potentially vast) white rhizomatous root system is shallow, it weaves around the roots of other plants, and sections of rhizome left in the soil can regenerate.