Why road verges are important habitats for wildflowers and animals

Nearly half of the UK's wildflower species grow in verges. These roadside spaces are refuges for many rare meadow wildflowers, which is crucial since the UK has lost 97% of its meadows since the 1930s.

Road verges cover an enormous area in the UK - they span about 500,000 kilometres, equivalent to driving more than 12 times around the Earth! Their total area is thought to be slightly larger than the Lake District National Park.

Museum botanist Fred Rumsey says, 'The sheer scale of the road verge habitat in the UK is pretty mind-boggling. In terms of providing habitat for our threatened wildlife, this huge network of linear strips is increasingly important.'

What are road verges?

Road verges are strips of land sited alongside motorways and other roads for various reasons: to prevent flooding, provide a safe place for drivers to stand if cars break down, store highway equipment and more.

Managed well, road verges have the potential to accommodate billions of plants and wildflowers, creating an important habitat for many of the UK's animal species - from small insects to larger mammals, birds, amphibians and reptiles.

Why are verges good habitats?

With hardly any people walking by, roadside verges are pretty undisturbed. Also, the soil is nutrient-poor. These conditions are perfect for wild plants to thrive.

The wildflowers attract pollinators such as bees, flies, moths and flower beetles. Other insects and spiders soon follow, as well as larger predators. These wonderful wildlife habitats can contain a surprising variety of species and can even help restore rare habitats elsewhere.

Verges that can accommodate a mix of open grassland areas, scrub and woodland will support the greatest diversity of species.

Flower gains and losses

Staggeringly, verges are home to over 700 wildflower species in the UK, nearly 45% of our total flora.

Twenty-nine of Britain's 52 wild orchid species grow in verges. Fred says, 'Recently there seems to have been a great increase in the pyramidal orchid (Anacamptis pyramidalis) in road verges but many of our other species can be found here, even some rarities such as the lizard orchid (Himantoglossum hircinum).'

The species numbers are impressive, but verges are vulnerable and can quickly be destroyed - in only a few hours, 17,000 orchids were lost as a road verge in Kent was demolished in 2019, Plantlife reported. As well as being home to rare orchids, the site had attracted numerous bees, 20 species of butterflies, common lizards, slow worms and a thriving population of small mammals.

Corridors connect and restore

Road verges provide physical links from one wildlife habitat to another. They are corridors that allow animals to move easily from place to place. Having this movement creates a healthier population as there is a larger area in which to find food, and the separate communities of animals can breed and mix genetically.

Without corridors, populations become isolated. This makes them weaker genetically and more vulnerable to any sudden changes in their environment, for example pollution incidents.

Verges can help to reconnect and restore larger habitats by allowing plant and animal species to disperse and repopulate different areas.

Meadow and grassland habitats

'Road verges primarily provide habitats for grassland species,' says Fred.

During the summer months, you might spot an abundance of cowslip, oxeye daisy, lady's bedstraw, bird's-foot-trefoil, scabious, knapweed and various native grasses.

But as well as being full of familiar flowers, road verges in some areas are refuges for rare or endangered plants. 'The pretty perennial flax (Linum perenne), for example, is a very rare and declining plant that has many of its sites on road verges,' says Fred.

Flower-rich meadows and other grassland habitats evolved over thousands of years through a combination of repeated hay cutting and winter grazing. Over time, a wide range of wildlife adapted to the specific conditions created by these habitats.

Today's road verges mimic these conditions.

'Most of the UK's grassland habitats are essentially man-made,' says Fred. 'They were created by ancient management practices such as grazing, which prevented them from becoming woodlands.'

Verges are mown to keep good visibility for drivers, but they're generally not kept very short. This suits some of the slightly bigger grassland plants.

'Plants like the knapweeds (Centaurea species) do well here,' says Fred. 'And very often, when on chalky soils, you can find the impressive yellow spires of their root parasite: tall broomrape (Orobanche elatior).

'There are other areas, particularly at the very edge of the road where the turf is often much lower and more open, where smaller plants can thrive.'

Our lost meadows

Most of Britain's meadows were destroyed by the intensification of farming methods after the Second World War. Huge areas of grassland have also disappeared due to urban expansion.

Fred adds, 'Many of the species that now thrive on verges, and are becoming more restricted to them, are those that once lived in our meadows, a habitat which has seen a massive decline, particularly in lowland Britain.'

By 1984 the total area of meadowland in Wales and England was estimated at just 3% of the 1930 level.

Fred says, 'I can remember as a student visiting a small protected road verge in Bedfordshire, which had a range of scarce and declining meadow species including the sulphur clover (Trifolium ochroleucon) and the crested cow-wheat (Melampyrum cristatum). These species are still on the decline, especially the crested cow-wheat.

Bringing back butterflies

Some verges contain chalk grassland, which is a nationally rare habitat and a favourite for butterflies. This is important as 76% of the UK's butterflies have declined over the last 40 years, according to the State of the UK's Butterflies 2015 report.

Without maintenance, key areas of chalk grassland are likely to be lost.

The Brilliant Butterflies project - which the Museum is a part of - is restoring and connecting sites in south London, including verges, to build homes for butterflies and other grassland species. With the help of volunteers, the project is creating 40 new butterfly havens around Croydon, Bromley and other areas. It aims to increase populations of small blue, grizzled skipper, chalkhill blue and brown hairstreak butterflies.

Katy Potts, the Museum's Biodiversity Officer working on the project, explains:

'As well as helping to restore existing chalk grassland, we are going to try to recreate this habitat in road verges, school playgrounds and on housing estates.

'These additional mini habitats will act as important links or wildlife corridors to the bigger chalk grassland sites. This will allow invertebrates to move between the different sites and hopefully strengthen the invertebrate populations on these important chalk grassland habitats.'

A valuable habitat for larger animals too

Road verges attract a diverse range of animals, including some of our shyer species.

Low footfall means adders and common lizards can bask undisturbed when they aren't hunting. Slow worms, frogs and toads are drawn by longer grass and a ready supply of invertebrate food.

Other animals found on road verges include shrews, hedgehogs, badgers, moles and, in some parts of the country, even water voles and otters. Bank voles, field voles and wood mice are the most common mammals that use road verges.

Sometimes verges also include trees and hedges. As well as providing homes and shelter for bats and other mammals, they provide nesting, roosting and vantage points for birds such as buzzards, kestrels and barn owls.

Close to the danger zone

Having grassland rich in potential prey so close to traffic zooming by is not without its risks to wildlife, however.

A habit of flying low puts barn owls at particular risk of being hit when they cross roads. Tall hedges force the owls to fly higher than the traffic, while branches that reach within a metre of the road will discourage the birds from hunting in this area.

It is important that barn owls are provided with enough suitable grassland habitat away from this danger. Other species will also benefit.

Changing species

Road verges aren't static habitats - the types of plants found there are changing and even 'new' or hybrid species are appearing.

Fred explains, 'The most dramatic changes plant-wise are the rapid spread of a range of coastal saltmarsh and cliff species that are adapted to saline conditions, which therefore can survive the saltiness created by salt-spreading in winter to keep roads ice-free.

'The most obvious is the Danish scurvy-grass (Cochlearia danica), which forms a snow-like band along central reservations and the edges of major roads. Its spread from coastal saltmarshes has all happened in the last 30-40 years.'

Species traditionally associated with more Mediterranean climes are also spreading.

'These species are possibly aided by our warming climate,' says Fred, 'but they are also spread by vehicles. One such example is the little grass Poa infirma. Once only known in the UK on Lizard Point in Cornwall, it is now a weed in the Museum flowerbeds.'

Meanwhile, Mediterranean orchid species are not only appearing on road banks but may be creating hybrids.

Fred explains, 'At one site in Dorset we have an interesting bee orchid (Ophrys species). We think it is a hybrid between our native fly orchid and the Mediterranean woodcock orchid, which may have arrived here as a windblown seed.'

Air pollution, brambles and nettles

Many of Britain's wildflowers prefer nutrient-poor soil. Air pollution from vehicle exhausts adds more nitrogen to the soil and creates an overgrowth of nitrogen-loving plants such as stinging nettle, bramble and rough meadow grass.

Although these can play a positive part in the ecosystem - as foodplants for caterpillars, for example - they can spread quickly, overcrowd other wildflowers and reduce the overall diversity.

Air pollution and poor management have reduced the flower richness found in verges by nearly 20% since 1990. Two bee-friendly plants, red clover and lady's bedstraw, are experiencing the most rapid declines.

Road verge management

Most road verges are maintained by national highways agencies or local councils. Their management includes cutting vegetation, removing invasive weeds, maintaining drains and fences, and controlling plant pests and diseases.

Vegetation can be removed to keep long-distance views, ensure visibility at junctions and, of course, verges can be managed to enhance wildlife.

Poor management of road verges

If managed poorly, verges can become overgrown with prolific native plants such as nettle and bramble, which strangle other rarer plants.

If flowers are mown too early, before insects have had a chance to pollinate them or before seeds ripen, the plant won't be able to reproduce.

Another common practice is leaving mowings on the verge - this makes the soil richer in nutrients, the opposite of what most wildflowers need. It also forms a 'blanket' that can prevent some species' seeds from germinating successfully.

Under management like this, summer-flowering plants such as eyebright and harebell are disappearing, leaving only the toughest plants to prosper.

Helping wildlife with good road verge management

Plantlife, in collaboration with Butterfly Conservation and the Wildlife Trusts, recommend simple changes such as cutting verges less frequently and later in the year, and using the plant power of yellow rattle to act as nature's own lawn mower - it parasitises grasses that compete with the wildflowers.

The wild plant conservation charity estimates that if all verges were managed for nature there would be over 400 billion more flowers.

Good road verge management enables existing plant populations to thrive and can be far more successful in supporting local native wildlife than planting colourful verges using pollinator-friendly seed mixes. While these do look beautiful and are often planted with the best of intentions, many contain species which don't have as positive an impact on ecosystems as you may think and may suppress native wildflowers.

The A354 Weymouth relief road in Dorset is a great example of how positive changes to road verge management can create a beautiful landscape where wildlife flourishes and is a result of collaboration between Dorset County Council and Butterfly Conservation. Many other local councils are making similar positive changes. 

As well as benefits for wildlife, road verges can provide commuters with daily (and sometimes their only) contact with nature and serve as buffers against noise and air pollution.