Joining up the verges

I’ve been paying more attention to the road verges since Sarah Pettegree wrote her excellent Guest Blog here and since Plantlife launched its verges campaign.

And so I was more susceptible to making the link between this press release from CPRE about lowering the speed limit in rural areas and the state of our verges.  The main justification for over-enthusiastic verge cutting is road safety.  We are all in favour of road safety.  If rural speed limits were reduced then the need for verge trimming for visibility at high speeds would also be reduced.  And therefore, if you like pretty plants you might want to support a move towards slower cars.  Isn’t it interesting how things join together?

After a twitter chat about damaged verges, Norfolk County Council provided some useful information.  One useful source of information for local authorities and others is the document: Well Maintained Highways: code of practice for highway maintenance management which is produced by the UK Roads Liaison Group.  Now, clearly, the ins and outs, ups and downs, of highway maintenance management are far wider and deeper than just how and how often verges in rural areas should be cut – almost all human life is here, and many of the words in this document are there to prevent human death so it is, indeed, serious stuff.

Nature conservation and biodiversity do get a look-in in this document – on pages 231 and 232.  There,  it is said ‘Highway verges and the wider ‘soft estate’ both have implications for conservation and biodiversity. Specialist advice should be sought on the management of these areas, in order to achieve the correct balance between safety, amenity, nature conservation and value for money.‘.  That sounds good – I wonder how often and how widely local authorities seek specialist advice on frequency and timing of cutting?

Later in this short section the document quotes Staffordshire County Council as advising that : ‘where fine stands of wild flowers are present in the verge, the timing of cutting operations should be varied to allow the flowers to set seed. Varying the times of cutting from year to year will help nature conservation/biodiversity, since a greater number of plant species will then be given a chance to flower and seed in at least some years. Such variations in the cutting regime should not take place, where it would be detrimental to safety due to obstruction of visibility.’.  So, although the road safety aspect is mentioned there is clear guidance that unless road safety is of overriding importance (and how should that be judged I wonder?) then varying the timing of cutting from year to year is an important and best-practice aspect of roadside maintenance.  this is because different plants seed at different times, but seeds live a long time in the soil, and so by varying timing each year should allow a proportion of plants to set seed and for those seeds to be added to the seed bank.  It might be worth asking your local authority whether they follow this practice and how often they override in on safety grounds and how those safety grounds are quantified.

I’m just guessing here really, but I suspect that this code of practice (which doesn’t look bad on the face of it and should be promoted to local authorities) has not been reviewed by Natural England or any other conservation experts – it’s just a guess because if it had been then perhaps the reference to English Nature (which ceased to exist in October 2006) would have been removed from this document which was updated in January 2012 (and many times since 2006); although how long its successor body, Natural England, will be with us is a matter of conjecture.

I would commend this example of verge management to you – it comes from the Cotswolds and seems to have been written with a lot of clarity and a lot of common sense.  What do you think of it? The suggestion that one cut after July is all that is needed in many cases and that cut material should be removed and composted hits most of the nails on their heads doesn’t it?  i would commend this to the UK Roads Liaison Group to include in their next update

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5 Replies to “Joining up the verges”

  1. As with all grasslands, verges need management and the timing of management is important. There is a myth that all flowers need to set seed every year and the consequence is that flowery road verges (and indeed many nature reserves) are left far too late before they are cut. There are arguments for a late cut eg late flowering species that lengthen the nectar/pollen season for invertebrates. But the downside of late cutting is that it allows competitive species of grass such as false oat-grass or tor-grass, or indeed late flowering competitors like ragwort, as well as underscrub species like bramble or clematis, to take over.

    Perennial grassland flowers to not need to set seed every year - far from it. Most are adapted to long lives and to set seed only occasionally. So an early cut, which can be very effective at redressing the balance between the "desired" flowers and the competitive grasses and "undesired" flowers is a useful tool as long as it doesn't happen every year.

    Varying the time of cutting from year to year is a good idea but the challenge is to effectively communicate that to the highway management teams and their subcontractors.

    A more pernicious problem is that verges are almost always topped rather than mown with the arisings removed. This has two impacts - one nutrients are returned to the soil, benefitting competitive species. Second the resulting mulch can smother smaller flowers and encourage the competitive grasses to proliferate. I think this is the biggest challenge of the two - the Highways Agency have been collecting arisings on parts of their soft estate (eg motorway verges) which have been identified as wildflower-rich for some years now. But again getting this incorporated into Local Authority management culture and practice a huge challenge, especially if it costs more, in these times.

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  2. Agree with much of the above, but cutting grass early in the summer can be disastrous for flower-dependent invertebrates if large areas are all cut at once - have seen this happen on verges and on reserves. Not a problem if flowery, uncut areas exist somewhere nearby, or if cutting is done sensitively and leaves mosaics or buffer zones of uncut areas, but danger is that machine operators want to be tidy and efficient and blitz all of an area at once.

    Real problem is that often there just aren't enough areas of flower-rich grassland to provide sufficient variation at a local scale.

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  3. The Cotswolds roadside management plan says that ragwort should be removed which goes against the recommendations of English nature who recognises it's value for wildlife and says that it's removal decreases levels of biodiversity which contravenes EU recommendations.

    Cutting of verges in late July would mean that here in Cumbria knapweed would not yet have come into flower and would be seriously detrimental to invertebrates.

    No mention ever seems to be made about cutting heights and type of cutting equipment. If a flail type device is used or any other device set too low then all caterpillars, insect eggs, small mammals etc will be pulverised.

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  4. Hi Mark,

    Not wishing to pull the focus from Plantlife's excellent campaign but a reminder that roadside hedgerows face similar threats from innappropriate management including a cutting-every-year regime which is destroying hedges and depriving our native wildlife of viatl autumn/ winter food. Annual cutting leads to the demise of hedgerows by the back door...as the Countryside Survey 2007 highlights, whilst hedgerow length remains stable at c. 470,000km in the UK, the proportion in good condition is 22% due to either over management or neglect. Its worth remembering that in a comparison of the ecosystem service provided by all Environmental Stewardship options, hedgerows came out tops. Please visit www.hedgelink.org for further details.

    Best wishes

    Jim Jones
    Hedgelink
    @HedgieJim

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  5. Thanks Martin - yes absolutely extending the season for nectar/pollen is very important, especially in areas where road verges are the last vestiges of wildflower-rich grassland and are especially important for invertebrates. But the danger is that if this becomes a conservation nostrum (which it appears to be becoming) then it leads to a change in the vegetation, where competitive species take over. And this results in fewer nectar/pollen sources, thereby defeating the object. For this reason we have to look beyond the verges themselves and start putting flowers back into the adjacent countryside, from where they have disappeared.

    Similarly I agree with DavidH's point - if the food plants for inverts are removed either mechanically or as a result of a change in the plant community due to mismanagement, this will also have a profound effect on invert popualtions and associated food webs. That includes birds Mark!

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