Should we learn to love weeds?

Shoes among weeds

They are the scourge of farmers and allotment holders the world over. But, as one naturalist pens a book in defence of weeds, should we see them in a new light?

Mention chickweed to my grandmother and her scowl - provoked by years of backache at the hands of her gardening nemesis - was instant.

That look is mirrored by woodland managers whenever they stumble across new shoots of rhododendron. And don't even whisper "Japanese knotweed" near those clearing the site for London's 2012 Olympics.

However, to naturalist Richard Mabey, weeds are not merely pernicious invaders, out to torment those who till the land. His first publishing job, west of London, was in a "labyrinth of breakers' yards, abandoned factories and filled gravel pits which was a riot of weeds," he explains.

"I just thought they were the most amazing, exultant plants, that were changing the environment for the better."

Nearly half a century later, the 69-year-old's view is unchanged.

The good weeds

Burdock flowers
  • Burdock (above): makes traditional drink when mixed with dandelion, and its sticky flowers - covered in tiny hooks - gave George de Mestral idea for Velcro
  • Jatrophacurcas: oil-rich fruit from this African scrub bush may be alternative aviation fuel - but plant may be invasive
  • Artimisia annua: relative of mugwort, used for research into malaria medicines

His latest book, Weeds: How Vagabond Plants Gatecrashed Civilisation and Changed the Way We Think About Nature, extols their oft-overlooked beauty, with references to poetry and painting.

And it praises their usefulness in food, medicine and industry.

But Mr Mabey goes further, saying weeds' resilience makes them "unconscious pioneers, growing first in disturbed land", such as bomb sites after the blitz.

He defends cogon grass, cursed for running riot in parts of Vietnam laid bare by American chemicals during the war in the 1960s. Other forest plants have been much slower to recover but Mr Mabey believes it is better that something, at least, is growing.

His conclusion that nature is "much more resilient" than its common portrayal puts him at odds with many peers.

But surely he won't defend those alien invaders, Indian Balsam and Japanese knotweed introduced to decorate Victorian gardens and now running rampant at an annual cost of hundreds of millions of pounds in clearance?

While Mr Mabey acknowledges their damaging effect, he says native plants may just fight back anyway.

He cites the example of Dunton Plotlands in Essex, a 1930s self-built estate. Later abandoned, they became overrun with unchecked garden plants.

But Mr Mabey says: "Over the last 40 years, native trees have begun to overtake these invasive plants."

Why I love stinging nettles

Probably Britain's most unpopular plants, but one of my favourites.

They support an amazing community of insects, from caterpillars and things that suck the juices from the plants, to all the predators that eat them like spiders and damsel-flies.

Nettles are also an important food source for many of our favourite butterflies, not least small tortoiseshells, which are in decline.

If you can tolerate these at the back of your garden, you might make a difference to Britain's butterflies.

And if you want something back, they are edible. Fold the leaves inward and you'll never get stung. Not the tastiest thing I've eaten but you can make soup out of them.

The author is at pains to say he is not advocating free rein for weeds but adds: "The idea that these things have wiped out English plants is only true in the short-term."

Many define weeds as "plants in the wrong place" but just where that place depends on whether you're a gardener, farmer or conservationist.

Dr Bob Froud-Williams, of the European Weed Research Society, says much academic work focuses on controlling weeds in agriculture.

"Without weed control, crop yields could be badly hit or - in worst-case scenarios - wiped out altogether," says the University of Reading lecturer.

Black grass, a British native annual weed, could be expected to halve the yield of a cereal crop if left unchecked. However, he says management - rather than eradication - can be advantageous, such as with "companion plants".

"The idea is that you use weeds as decoys to attract insect pests or, alternatively, because they give off certain deterrents," he says. "But the key is to keep them in balance and with agriculture."

Some practices, such as using high levels of fertiliser, can help weeds proliferate and become more competitive, he says.

And the bad weeds

Japanese knotweed
  • Japanese knotweed (above): Colonises river banks, woodlands, grasslands and coastlines but particularly urban areas. Grows through walls, tarmac and concrete, reproducing from tiny fragments
  • New Zealand pigmyweed: sold for use in fish tanks or ponds, a tiny fragment can regrow into dense mat. Frost resistant, it's spread across UK and can dominate a site within three years
  • Rhododendron ponticum: Gardeners' favourite and often not thought of as a weed, but grows many metres tall, wreaking havoc in woodland. Thick leaf canopy blocks light to native plants, lichens and mosses, while releasing toxins into soil

Citing philosopher Ralph Waldo Emerson's opinion that a weed is "a plant whose virtues have not yet been discovered", Dr Froud-Williams says they fulfil an important environmental role.

"With concerns over the decline in bee populations, weeds are an important source of nectar and pollen, particularly when a number of crop species are unavailable."

Their importance in food webs is highlighted by the declining farmland bird population, attributed by some to herbicide use.

This has been acknowledged through European funding for farmers who leave uncropped margins to aid wildlife. Some such agri-environmental schemes have had startling results.

Andy Byfield of Plantlife, a charity campaigning to preserve Britain's struggling species, says one Kent farmer agreed to stop spraying herbicide on an entire arable field.

Within three months 10,000 broad-leaved cudweed plants had sprouted - the second-largest UK population of this endangered species - along with various poppies.

Mr Byfield says the seeds of cornfield plants can lie dormant in this way for decades, or even centuries.

But despite their resilience, he disagrees that Britain's indigenous plantlife will survive the invasion from "sprawling, smothering" species from "over the garden fence". The UK's limestone cliffs are being populated by Mediterranean and Chinese species, such as holm oak and cotoneaster.

Viewing massed rhododendrons in Tokyo Rhododendrons: Beauty, or beastly weed?

And while some native plants may take seed in the area, Mr Byfield believes the native grasses they oust will be gone for good.

"I simply can't believe that these places will miraculously recover," he says.

However, with a great unknown remaining over the extent to which the UK will be affected by any climate change, Mr Mabey has one final word.

"There might come a time when we're grateful to some of these invasive plants because they will move into places which have been vacated by native species."

Below is a selection of your comments

As an RHS student, we were taught "a weed is a plant growing on the wrong place" - but in my garden some of the plants growing in the wrong place have to be removed as they strangle those growing in the right place. I leave selected patches of nettles for butterflies and burdock comes from the adjacent fields. It is not a case of eradicate, but the control does take a lot of hard work.

Rachel, Oxfordshire

I must protest that you have once again condemned rhododendrons when in fact only one species can cause problems, and only then when it is allowed to grow wild. This is the ordinary purple rhododendron ponticum, other species and modern hybrids are perfectly normal attractive bushes which can be safely planted in the garden.

John Rees, Surrey

We need to learn to appreciate our native species more and stop venerating the exotic. We risk our wildlife being deprived of habitat and pushed out. It is such a shame to see Himalayan Balsam taking over apparently everywhere. Loved the vampiric dodder film - also love nettle soup.

Linda Pearson, Leeds, England

Nettle Soup - best made in spring. Pick (with rubber gloves on) a carrier bagful of young nettles - just the top 4-6 inches - and wash them. Gently fry a large, chopped onion in oil or butter. Add 3 medium-sized potatoes, peeled and chopped into chunks, and water to cover. Add stock cube and/or any of marmite, soya sauce, mushroom ketchup, to taste. When potatoes are soft, add nettle tops (top up the pan with water if necessary) and black pepper. Cook for another 10 minutes, then puree in the pan with a soup wand. Serve with grated cheese and crusty bread.

Anna, Orkney, UK

I just like the poetry of weeds. They grow where they choose to go, not because anyone decided that that's where they ought to be. We have snow-in-summer in our garden and seeing the way it takes root in the cracks in the concrete and lives there is inspiring. The same goes for dandelions that you walk past without even looking at - just a beautiful mass of bright yellow, there because it suits them.

Sophie, London

There are some weeds which despite their beauty are dangerous. Living very close to the River Tweed we struggle annually with giant hogweed invading not only the river banks but also gardens and indeed anywhere in the village. Beautiful as it is from a distance, any close contact with it painfully burns the skin and these burns will recur for years to come when sunlight hits the affected area.

C Jobson, Wark-on-Tweed, North Northumberland

Curious coincidence. This very morning I've just picked up a second hand copy of Richard Mabey's Food for Free book, first printed in 1972 for 20p. It's a shame that rhododendrons and the knotweeds aren't edible.

Paul, Eastbourne uk

Each garden seems to have its own specialist weeds. In my previous garden in Yorkshire, it was horsetail. Here in Cambridgeshire, not a horsetail to be seen. But I have abundant yellow corydalis, herb robert and a rather nice little weed called creeping wood sorrel. All these defy eradication so I have more-or-less given up. But I do have two very good weeds. Forget-me-nots crop up everywhere and are easy to move to suitable locations. And since I first grew sweet williams a few years ago, they have spread very well and are a useful free addition.

Jack Harrison, Great Chishill, Cambridgeshire, UK

My small back garden is frequently invaded by Spanish bluebells which are apparently a foreign invader, but I like the flowers. My house is built on an old factory and the soil is poor and quite contaminated so I'm glad something attractive flourishes.

Peter, Notts

Had a conversation about what I miss from the UK since emigrating and dandelion & burdoch was on my list - none of my other expat colleagues, a mixture of Americans, Australians & Europeans, had ever heard of it. A fantastic drink.

Anthony, Phnom Penh, Cambodia

As an allotment holder I have a begrudging admiration for the resilience of "weeds". Reading this, I'm reminded of research into phytoremediation - utilizing plants to remove toxins and contaminants from soils in locations such as Chernobyl.

Simeon, London

We should certainly love weeds, they are part of the web of life and some are very beautiful. The poppies of the battlefields have given us a powerful symbol of the futility of war. A meadowful of weeds is buzzing with all sorts of life - a field with one type of grass isn't. I'm hoping the current financial austerity will mean that councils cut grass verges less and we can have our wonderful wild flowers (and insects) back again. In my garden I let some small contained areas run riot (including two square metres of lawn) and I have a bucket of stinging nettles - much appreciated by the insects and then by birds in turn.

Diana, Bristol

I've always liked oxalis - the pretty little pink flowers which are far more resistant to local snails than any other flowers we've had the misfortune to try and grow.

Jenna, Leigh-on-Sea

Some native weeds, such as the cornflower, are endangered, whereas some invasive species, such as Rhododendron ponticum, are endangering our habitats and getting rid of them has huge cost implications. On the other hand, some non-native alien species like buddleia provide a rich food source for our insects. To generalise and bunch all of these together is a little ridiculous.

Laura, Solihull

Chickweed is very good for relieving inflammation - I've eaten it and can vouch for it. I understand pounding it up and applying it externally also works.

Lynn Kohner, Seattle, USA

I only pull up weeds that overtake my garden flowers. Every year we enjoy red campion, honesty, various willowherbs, feverfew... things like herb robert can be a nuisance, but they are easily controlled, and a starry delight growing out from behind old flowerpots. And you can't beat a mass of dandelions on a sunny morning.

Annie clarke, Manchester, UK

I like the Emerson quote, as it applies to plants with medicinal as well as aesthetic properties. "If it's pretty, it stays" isn't a bad rule of thumb for a domestic context (and the bumblebees seem to agree), but naturally, industrial agriculture needs much more careful management. I inherited a mature garden when I bought my current house some years ago, and while I keep grass mown and hedges trimmed, I've let everything else do its own thing, and I've only lost a couple of plants.

Dave, Old Basing, Hampshire

Weeds are plants we have forgotten the use for. I love nettles, they provide compost for my garden, habitat for essential insects like ladybirds, they provide food and interest for my chickens, they provide food for me in various ways, they can be used as a liquid plant feed and a mulch. Dandelion leaves are edible in salads, the roots can be dried, roasted and ground for coffee and the flowers can be fried in batter or baked into bread - or used for that cake recipe above.

Andrew Trousdale, Leeds

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