Sunday, 10 June 2018

Are nettles really taking over our roadside verges?

And what we can do about it?

Umbellifers in nitrogen rich ground
A scientist has proposed that excess plant nutrient nitrogen is released by car exhausts and its build up in roadside verges encourages coarse weeds such nettles, brambles and hogweed. The popular press has mangled this story and it is now received knowledge that this is a national crisis. Nettles have had a sudden image transformation from the darlings that ‘every garden should have them’ to being coarse monsters that outgrow the wild flowers.
I suggest that we should concentrate on car exhausts because they might be killing us all and not to worry too much about the nettles.

Delightful coarse growing vegetation
I am sorry to return so soon to the confusion between weeds and wildflowers and that frequently they are one and the same. Only in my last post I marvelled at how dandelions and buttercups had returned to roadside verges since we desisted from herbicide spraying. 
The new opinion is that this transformation might be not be so desirable and invading coarse weeds such as dandelions are a bad thing. Or have I got it wrong and dandelions and buttercups are good and only nettles and hogweed are bad?
Dare I suggest that any so called weed is alright as long it is in the right place.

Pain at first. I have sprayed a three metre length of verge to kill brambles, nettles, ragwort and couch. I will encourage fine grass, buttercups and dandelions to replace them.
No one explains that any coarse weed problem has in truth arisen with the reduction of spraying and even less likely that you will be told that intelligent directed spraying might be the remedy. 
It might surprise you I do not advocate this! 
The dead hand of bureaucracy that indiscriminately sprayed in the first place is incapable of sensitive roadside plant management now. I do not of course reject inspired herbicide management under local control

Lovely, but ragwort is deadly to animals if it seeds into grazed fields 
I became alerted to this perceived problem when half listening to John Humphreys as I invariably do when writing my blog. As so often with scientists (and gardeners) he was not the rottweiller he is with dissembling politicians but was in his pussycat mode.
He can be a mixture of amused confused condescension and fawning acceptance of a scientist’s crackpot ideas (and especially so if nonsense is uttered by some high profile media gardener). 
In this case the news item had already been garbled by the newspapers and the scientist himself when he brought the problem of nitrogen run off from farm fields into the equation.

Confusion between nitrogen pollution and high soil fertility

Here the roadside is probably infertile and this legume thrives because it fixes its own nitrogen
It is fashionable these days to create infertility by removing vegetation to make gardens and landscapes amenable to wild flowers. I have no difficulty with this and admire wonderful wildflower meadows that have been so created. 
It still however goes against the grain for me personally when all my instincts are to create healthy soil as a result of sound soil management.

It would be pie in the sky to expect motorway verges to be like this
I see everywhere gardener’s zealously making a nitrogen rich store of goodness by way of making garden compost and delighting in how it makes plants healthily grow.
In contrast it is now sometimes wrongly perceived as environmental pollution for farmers to create fertile sites ‘that takes years of endeavour to extinguish’
To me it is good for mankind that soil can retain its organic fertility and nutrient store for quite a long time.
It’s not even that fertile soil as such is bad for wildflowers. It's just that the nettles grow so much better and smother them. I believe that there is potential for gardening methods that will grow wildflowers without denuding the soil.
Old gardeners would tell you that overgrown allotments with luxuriant nettles might be hard work at first but have wonderful potential.

Let us not solely ‘blame’ nitrogen for long lasting soil fertility. Indeed the very different problem of nitrogen pollution arises from the high solubility of nitrate when it washes away. The most long lasting soil nutrient is phosphate which in many soils after two hundred years of farming with fertiliser is too high. Major nutrients such as potash have varying soil retention depending for example whether it is sandy or clay.

Do we have a problem on roadside verges?

No problem here with sensitive infrequent mowing
I don’t doubt that car exhausts might be a source of extra nitrogen. I do doubt that it is sufficient to matter in other than areas of very dense heavy traffic. I did notice on my recent trip to Liverpool that they had plenty of examples of nettle rich verges.
Very much less so along the M62 motorway where in places coarse colourful vegetation such as dog daisies, buttercups, campions, umbellifers and a little earlier in the season dandelions, were lovely. Central motorway edges were somewhat devoid of vegetation other than grass.
I would suggest that most of the landscape reflected levels of management - mainly mowing - rather than exhaust pollution.

The trees lining the M62 on that recent Spring day were strong and verdant. Nitrogen is essential for healthy plant growth and motorways are generally constructed with spoil rather than soil. Perhaps a little extra nitrogen has been a good thing?

Do any extra nutrients alongside roads come from agriculture and elsewhere?  

In the countryside I am sure extra nutrients spill in from farm fields
Some surely must where ground is higher and soluble nitrates leach and phosphate rich soil erodes down. Leaves from trees blow and alight and even create organic rich pockets. In terms of plant growth the diverse habitats created might be a good thing.
Salting of roads has certainly favoured salt loving wildflowers to spread from the seaside.

What to do about it?
It was when the mad scientist (I might yet eat these words) suggested ‘solutions’ to his perceived problem. He fell back on the idea of removing fertility on roadsides by mowing and carting vegetation away.
How much would that cost? How much extra carbon dioxide would be created with extra machinery and transport. What on earth might we do with that extra vegetation. Our amateur composts might become even greater rubbish than now.
What about the extra roadside pollution created?

Posts prevent parking (and allows wild flowers to grow)
It’s alright to want delicate wild flowers to grow in favoured roadside habitats. It is wonderful to delight in rare plants alongside country roads and in serendipitous habitats accidentally arisen. 
Let real local native vegetation thrive in the verges and hedgerows and let us do what we can to conserve it.
But don’t expect to achieve tracts of of feeble yet lovely wild vegetation along busy roads.

Roadside fertility might not be such a bad thing
I do not believe that the way forward is to reduce general roadside fertility. We need strong growing stabilising vegetation and all the better that the buttercups are beautiful.

Even 'alien' invaders here in Derbyshire countryside stabilise the verges
I have written extensively about Cathi’s grass verge which borders our country road that carries perhaps 200 lorries a day that fly by. Their trajectory veers when they meet oncoming traffic.
I am grateful to coarse grass, silverweed and buttercups for constantly growing back where the edges erode.
(I hasten to add only about a metre in my case, the rest is fine grass and flowers)

I am grateful that coarse vegetation quickly grows back when lorries cut up the edge
I reviewed the lovely book 'Wild flowers on the edge'
I wrote about corn marigolds on the edge of a farm field

Confusion between weeds and wild flowers

Friday, 1 June 2018

Blame the operator not the weedkiller

Bee bum plant for bumblebees
But it is damned as a weed!
In my recent post about the excellent new book from the Bumblebee Trust they repeated the mantra about not using insecticides and herbicides in your garden if you want to encourage bumblebees.

I have no problem with the damning of insecticides in this context. After all insecticides are designed to kill insects and their indiscriminate and ignorant use can be a disaster for bees. In my own gardening I only rarely use insecticides. Only twice in the last 12 months and that was on house plants!

It's the lumping together of herbicide and insecticide that provokes my ire
Although I cannot promise no weedkiller exists that poisons bees, herbicide toxicity to animals is extremely rare and all readily available weedkillers are extremely safe. (Orders of magnitude safer than the garden machinery you regularly use)

This is not the public image of these useful gardening aids. Indeed the word ‘weedkiller’ is almost synonymous with ‘poison’. Only exceeded by ‘ratkiller’. The latter is particularly ironic as the principal ingredient of most common rat and mouse killers is the warfarin of medical use.

Verbena seeds itself all over and to some gardeners is a weed
The ignorant are frequently surprised that my glyphosate managed gardens are so rich in wildlife. The even more ignorant expect my gardens to be sterile.
I claim without blushing that my gardens are ecological richer than most.

It’s what you do with things that causes the problems
Undoubtably weedkiller in the wrong hands can do considerable harm. How much ecologically richer are our roadside verges and hedgerows since they are no longer sprayed.
In contrast sensitive use of weedkillers can be used to create beautiful landscapes of flowers as I do.

Spray out the nettles and wildflowers can grow
As a small example a landowner I used to work for who was renowned for his beautiful acres of wild flower meadows would in his own words ‘spray out the nasties’ using MCPA or 24D to spot treat and kill such as nettles, thistles and hogweed. In their place the wildflowers grow

Fools jump in
Almost any gardening or agricultural practice can be maliciously and harmfully used. How innocuous are agricultural drains but they can be used to destroy wetlands. 

The chain saw is a useful tool but look what it has done.

There is good and bad in ploughing, digging and most soil cultivations.

Mow the buttercups later
Even the mower is regularly destructively used. Yesterday (May 10) we drove over the wolds to Filey and marvelled at the beautiful nectar rich dandelions at the roadside. On the way back we passed council workers mowing them down.

Public image of herbicides
In the public mind weedkillers are toxic - literally so. I deny this. The world has gone mad when it seeks to outlaw ‘roundup’ the safest pesticide ever invented.

Simple things reinforce public misinformation. For example that wretched lovely toxic weed ragwort. Farmers fear it because when dead it is highly palatable yet deadly. When for this reason the uninformed read that animals need to be kept out of sprayed fields they deduce that the same MCPA, 24D and similar, will poison pets on their lawns.
Cathi is concerned that in her own verge such ragwort will spread to her fields
As an aside I might mention that I recently posted about spraying out nettles in Cathi’s field. When the nettles went yellow and died her soay sheep devoured them with great gusto. I understand nettles are very nutritious.

The sad thing about roundup is that it is damned for what it is meant to do - kill weeds. It does what ‘it says on the tin’ and does it superbly. With this comes all of the advantages of minimum cultivation, maintenance of soil fertility, organic matter and worms. Worldwide million of tons of carbon stay in the ground as a result of the enlightened soil management it enables.

And yes some of those weeds are wildflowers. Surely the way forward is to benefit from the high yields facilitated by good weed control and set agricultural land aside to grow nectar rich pollinators and in so many other ways encourage nature

Bindweed makes a distinct white honey
Flight of fancy
Sweet and toxic
Writing these words set be thinking as to how many real agricultural and garden weeds actually produce copious nectar and/or pollen. If anything is to justify weeds displacing crops, genuine wild flowers and pollen rich garden plants it would be useful to know.

Of course if something is desirable it is not a weed by definition! Perhaps you should consider growing these sugary morsels?
  1. Dandelions. If these were difficult to grow everyone would want them! Although most dandelions set seed vegetatively without fertilisation they do produce generous nectar and are much visited by bees. They are very easy to grow.
  2. Himalayan balsam. Banned in the countryside it produces so much honey that it is for obvious reasons affectionately known by countrymen as the bee bum plant. (Its head is down slurping the flowers). Extraordinarily beautiful it will take over your garden.
  3. Brambles. I grow a wonderful seedless blackberry. One plant satisfies all our culinary needs. Why not go the whole hog and do nothing and in five years your garden will be five foot high brambles - in my view Britain’s worst weed but good for the bees.
  4. Ragwort. Bees love this beautiful aggressive weed that might grace your garden. Pity the honey might be poisonous
  5. Epilobium. This seed born perennial weed is the bane of my life. Fail to control it and it will give the brambles a fair run to take over your garden. Nectar and pollen rich it makes a nutritious honey
Epilobiums are the bane of my life (but not for bumblebees)
Let creeping thistle creep five metres a year into your garden and the bees will love you. Not so your neighbours inundated by seed
Your epilobiums won't make you popular either
I see it now, if you want to encourage bees don’t use weedkiller and grow weeds!

Talk about flight of fancy. Last weekend Alwys Fowler, tongue in cheek, suggested that gardeners eat Japanese knotweed to death and also observed it makes excellent honey. She added the mandatory rider of course you would not eat it if it had been sprayed. Nor would I. (but it would do me no harm)

I have written before about the blurring of wild flowers and weeds

At Jervaulx Abbey they imaginatively grow real weeds on the masonry (but spray out the nettles)

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