At Eden we tell the story of man’s relationships with plants, cultivated the world over for food, medicine, materials and beauty. But why is it that some species are nurtured by man, in fields and gardens, while others have ended up on the wrong side of the fence – as ‘weeds’?
What is a weed, what makes them so rampant – and how can we learn to love them? Hannah Bullock spoke to nature writer Richard Mabey, who shed some light on the species that grow in the spaces between.
The word weed is a cultural label
‘Take, for example, the rise and fall from grace of common horse tail. It’s now regarded as a pernicious weed in gardens, but is actually a perfectly brilliant scourer, and was used for cleaning pewter right up until Elizabethan times. I’ve used it as a pan cleaner and it does work!
‘A bundle of it can also be used as fine sandpaper, because the marvel of the plant is that it deposits minute silica crystals on the outside of its fronds.
‘Horse tail is one of the most ancient plants, a relative of species that were around when the coal measures were being laid down several hundred million years ago. They’ve had time to evolve some canny survival techniques, like their very deep underground stems.’
In reality, all plants are useful
‘When we consider how ‘useful’ a plant is we tend to think of its practical and immediate use to humans, asking ‘can you make materials out of it, can it beautify our gardens…?’ But any organism which contributes to the smooth and rich workings of the planet is by definition, useful to us, because it keeps the great machine going.
‘Consider the host plant of a predatory insect that preys upon another insect, which eats one of our crop plants. Through a long chain of connectedness, this first plant is actually as useful to us as the crop plant.’
Weeds thrive on human ambition
‘The human definition of a weed is a plant that has got into the wrong place; into a space that humans want to use for something else.
‘The major failing in our understanding of them is that they are where they are precisely because of our habit of doing rough things to the ground.
‘Long before farmers and developers came along, a whole raft of often unrelated plants evolved to take advantage of disturbed land, such as changes on the edge of tide lines and flood plains, falling scree or disturbance cause by volcanoes.
‘Most of them were annuals that dropped their seeds and were carried far and wide, or had root systems that broke off easily and were capable of generating new plants.
‘As soon as humans created copies of these naturally disturbed environments – ploughing soil, having battles or undertaking development – these species had a whole new range of territories to invade.’
Weeds have hitchhiked on humans throughout history
‘Kentucky bluegrass sounds from its name as American as apple pie but it’s actually annual meadow grass, thought to have arrived with 17th-century European settlers as seeds in the mud on cattle’s hooves. It very rapidly took over the prairies, outcompeting the much more delicate indigenous grasses, which had never experienced the hooves of grazing animals before.
‘By modern conservation standards it would be regarded as an invasive alien, but in farmers’ terms the spread of this nutritious fodder plant was a great boon.
‘Another common weed of urban spaces, Canadian fleabane, came over here in the most bizarre way; its seeds had been used inside a stuffed bird, and when it was thrown away these established themselves on the South coast of Britain. I’ve seen the plant on roadsides in France and industrial sites across Europe – all thanks to that one shipment in a stuffed bird.’
We gardeners need to learn to live with weeds
‘Of course I remove weeds when I need to complete a project in the garden, so I’m not being holier than thou. But my advice is to avoid that kneejerk reflex of ‘oh, I know that’s a weed, therefore I must get rid of it’ and instead ask yourself ‘why is that weed growing there?’ It hasn’t come there entirely arbitrarily; usually it’s your fault!
‘As you start to trace the story of how it arrived there, you begin to realise that it’s an individual with a character and modes of behaviour – which may make it possible to find a modus vivendi with it.
‘I’m happy to have weeds abundant in my vegetable patch in between the rows – particularly shallow-rooted ones. They brighten the place up, they’re great moisture conservers and they harbour a much greater variety of insects, so your pests are likely to be fewer.
‘If you opt for a dedicated ‘wild patch’, the bigger the better. People get very sentimental about these, but they may have to be ugly and they’ve got to be really wild. You have to judge it from the wild’s point of view, not your own. No butterfly or bee can grow into a nectar-eating insect unless it starts as a grub, which eats things like nettles and dock.
‘If you want pollinators in your garden, you’ve got to allow weeds for caterpillars to eat, as well as beautiful sweet williams and buddleia.’
My favourite of all is the giant hogweed
‘It’s so utterly magnificent; an 18-foot-tall cow parsley with flowers the size of lorry wheels. I also love the little speedwells that grow in the spring and can turn a whole lawn blue for a week.’
Richard Mabey is author of some 30 books including the bestselling plant bible Flora Britannica, Food for Free and Nature Cure. A regular commentator on the radio and in the national press, he is also a Director of the arts and conservation charity Common Ground and Vice-President of the Open Spaces Society. His latest book, Weeds: The Story of Outlaw Plants, is published by Profile Books. Richard Mabey was in conversation with Hannah Bullock.