I’ve always been a big fan of urban hedges. I reckoned that – like trees – they must help manage water runoff and moderate temperatures. Planting relatively large numbers of mixed native plants together in cities had to be good for wildlife too – maybe even more so than trees because of their diversity, volume and value as a wildlife corridor and resource. I had supposed – partly because of that – hedges in cities would also be good for human mental health.
It turns out that they have much more significant and direct benefits.
We have thought for a while that trees can reduce particulates from, for example, car exhaust. The plants either absorb them through their stomates or catch them on their leaves, to be washed off or fall to earth in the autumn. Earlier studies suggested that well positioned trees could reduce particulates by up to a quarter.
It makes sense that hedges should be pretty good at this too. They’re not only denser but also at a better level to intercept exhaust fumes. A recent study supports earlier findings supporting this. Although its efficacy varies according to conditions, a roadside hedge can reduce near road air pollution by up to over 60% in some cases (including the cancer causing pollutant black carbon). Remarkably, hedging is not only much more effective than trees, but also seems to be more effective on its own than in combination with trees.
We have a massive problem with air pollution in our cities. The UK has regularly breached legal standards in London. Many thousands are dying from the consequences, and heart breaking individual stories are emerging. A recent WHO report found that over 4 in 10 primary school pupils in the UK are breathing dangerous traffic generated particulates.
The government seems short on practicable ideas to tackle the issue, at least in the short term. Why not plant hedges?
We recently planted this specially selected triple width mixed native hedge at a school in Yorkshire. It will be a dense filter (and impenetrable barrier!) soon enough, running over 100m along the school’s boundary.
Planting hedges in cities is simple and cheap, and they are demonstrably effective at reducing harmful pollution. Mixed native hedges like you would find in the country are attractive too, with lots of wildlife value. What’s not to like?
Solar farms, or parks, are going to come in for a lot of flak. Photovoltaic panel prices are a third of what they were three years ago. Generous government support and ambitious targets mean that they’re sprouting all over the countryside. For developers and landowners they’re a no brainer, offering spectacular guaranteed yields. They seem to be a much better solution to meeting our renewable obligations than wind farms, too.
Everyone loves the idea of renewable energy, but the reality can be less attractive. Particularly before landscaping, solar farms can look pretty enormous and industrial. The visual impact of solar farms is a difficult thing to assess, and provokes fierce argument. A proposed site might look fine on a map if it’s not visible from any “important” or regularly used sites or footpaths. If you live in the one house directly overlooking it you might feel differently.
Many developers are motivated by purely economic interests and fail to engage local communities. Worse, they just ignore them, knowing they can get planning permission on appeal if necessary. The planning process is struggling to balance local opposition with national policy. We can take some of the heat from this process by improving the way solar farms are established and run.
Mitigation requirements are generally modest, and mostly relate to hedges and hedge planting. They should be more ambitious. Sure, reinforcing, planting and letting hedges grow is helpful, but why not do more? Solar Farms actually represent a great opportunity to create biodiversity hotspots. The green deserts they replace are generally “improved grassland”, and have very limited value for biodiversity – contrary to most people’s perception. Solar farms, surprisingly, can be much more interesting.
For a start solar farms are fenced, which prevents destructive larger mammals (including humans!) getting in. This is great for flora, reptiles and ground nesting birds, for example. There’s also typically a margin between a surrounding hedge and the security fence. Why not establish a floristically enhanced margin here? Or if you were keen to encourage owls, for example, plant tussocky grass to help the vole population.
Currently, the areas between and around solar panels in most sites are either sprayed off with herbicide or cut regularly, to keep grass and weeds from obscuring the panels and scrub from getting established. Why not have grasses and wildflowers there instead? Although they will actually need less management, planners should require a management plan for these areas too. The aesthetic and environmental gains are obvious. There are also economic advantages; the cost of maintaining a carefully planned wildflower and grass mix is much lower than repeated large scale spraying or grass cutting.
These areas can also be tweaked to encourage particular wildlife. Perhaps the local community would like to encourage skylarks or a rare type of bumblebee (which is happening at one of the sites we’re involved with). The plant species can be selected and managed to suit.
The layout of solar farm panels can be helpful for biodiversity, too. Directly below them is dry, shaded and sheltered. At the base of the panel there is water runoff and more light, and in front of each row light but less water. These micro-habitats are ideal for encouraging a tremendous diversity of flora and, ergo, wildlife.
When stipulating planting schemes, planners can also be picky about provenance. It’s a great opportunity to help British suppliers of plants and seeds – like Habitat Aid! – as well as to do the right thing ecologically. Let’s learn from Ash Tree dieback. Hedge plants for solar farms shouldn’t just be native species but sourced from British stock grown in Britain. We can be even more local with wildflower and grass mixes. We can supply seed harvested from sites all over the country.
There are other potential uses for solar farms. Use orchard trees as part of any screening planting – and why not plant them with local varieties of fruit tree? I know of one site where they’re rearing queen honeybees behind the fencing, undisturbed by vandals and badgers. This stuff isn’t unreasonable or unrealistic. We are partnering two of the best solar farm developers in the country who are doing just this kind of thing:
“If you build it, they will come” is the strapline for the new RSPB adverts. Initially I thought it was just ripped off from “Field Of Dreams“, (another) odd but entertaining Kevin Costner movie from the eighties, “If you build it, he will come”. My second thought was how brilliant it was. I’m constantly trying to get across the attraction of playing God and creating your own little patch of biodiversity by bringing animals into your garden.
Then I had a chance to think about it again. I was at Hampton Court helping promote the bumblebee app in the bee tent next to the RSPB, so I could ponder on what was bothering me. Their display had all sorts of stuff you could buy (from the RSPB’s online store) or build – bird boxes and feeders, a shed, hedgehog house, bee boxes, hibernaculums (hibernacula?). What it didn’t have – and nor does the TV ad – is much by way of plants. In fact the garden in the ad and at Hampton Court look ghastly – drab and uninteresting – presumably in case attractive plants detract from the cute signs and the cute animals.
Isn’t this a bit odd? Fantastic wildlife gardens aren’t generally filled with paraphenalia. They are designed and managed sensitively and planted well. If we do feel compelled to “build it” can’t we build it to look good too, using landscaping features like dry stone walls, rather than a range of reasonably priced wildlife shelters or mini Eeyore homes? I’m building a dry stone wall at home as a retaining wall, which won’t win gold medals but will look great, as well as providing a home for all sorts of wildlife.
More fundamentally, as a final thought, shouldn’t we “plant it” rather than “build it”? I thought plants were where gardens and ecosystems started. And can’t we “plant it” to look nice too?
Much of the Somerset Levels, an hour west of us, is still under water. This video was taken in late November down the road from Burrow Hill, where the lovely Somerset Distillery is based:
Three weeks later there’s a sorry mess of abandoned cars and floating hay bales in a scene more like a post-apocalyptic disaster movie than rural England:
It’s not making news, but that doesn’t make the plight of the folk down there any better. This is an A Road that’s flooded, between Taunton and Glastonbury, and it means a 15 mile detour around the mess that was the River Parrett. Better a mess here than in downstream Bridgwater, I suppose. The Environment Agency estimate there are 43 million tonnes of water currently lying on the levels, which sounds like a lot to me. They reckon the road will be closed until after Christmas – at least. It was closed in May as well.
What’s to be done? Of course the Levels have always been liable to flooding, but in recent history we’ve felt we’ve been able to control that. In earlier years Sumorsaete was, literally, the land of the summer people, and parts of the county abandoned to the water in winter. After hundreds of years’ work I can’t imagine there are any more flood prevention schemes that can be introduced, even if we could afford them. The more extreme weather events we are seeing are showing no signs of mitigating. Sea levels will rise. The farmers are all going bust and their fields and houses are unsaleable. When will government start to face the reality of global warming that’s staring the Burrowbridge locals in the face, and start thinking the unthinkable about land use in these areas? Could we pay for land to be added to the astonishing – and valuable – wildlife reserves already in the area, for example? Things can’t go on as they are.
We forget why and how to plant a native British hedge. We take them for granted. Country hedges a history going back to the bronze age, making them one of the oldest man made features in the British landscape. According to Hooper’s Rule , here in our bit of Somerset we’re surrounded by medieval hedges.
Native plants make a good, fast growing privacy hedge which is recommended for security. They’re also beautiful things and a fantastic resource for wildlife and foragers. Mixed hedges using native species are easy to recreate and manage, and I’m always surprised that more folk don’t go for them.
Why a Native Hedge?
Our native British hedge plants seem to me to be a bizarrely under-utilized resource in urban environments in particular. Here they can significantly help to reduce pollution. Perhaps people associate them with unruly country hedges, when they want a clean and tidy look. In which case, why not suggest a clipped single species? Other native plants can be as architectural as yew or box; use Hawthorn, for example. Like Blackthorn, a great security barrier, beautiful in spring, and fruitful in autumn.
For summer colour, completing all year round interest, punctuate with our native Honeysuckle, Lonicera periclymenum, or Dog rose,Rosa canina. To my mind, though, the more species in a hedge the better, if for no other reason than increasing its associated biodiversity. Structurally mixed hedges look sounder to me as well; you need a good mix of suckering species like Blackthorn and Hazel to continue to give it a good thick base.
This all means a traditional hedge is excellent for security. If they have kept cows and sheep out for hundreds of years, they’ll deal with people too! Hawthorn and Blackthorn – the clues are in their names – make impenetrable barriers. Hawthorn’s synonym – “Quickthorn” – also tells you how fast it will grow
Native hedge plants make good visual screens too. Beech and Hornbeam keep their leaves in hedges, and Yew, Holly and Privet are also evergreen.
Hedges and Wildlife
As with all our native plants, common hedge species have unique relationships with our native fauna. When they think about the food that they provide most people think about the berries for birds and small mammals – and larger mammals like gardeners! There’s a largely unnoticed community of animals further down the food chain, however, which depends on a hedge for other forms of sustenance.
Our butterflies and moths have unique relationships with our native plants, many of which you can include in a hedge. The Yellow Brimstone, for example, lays its eggs on Buckthorn, on which its caterpillars feed exclusively. Brown Hairstreak has a similar relationship with Blackthorn.
Think of the number of plants in a native hedge and you can imagine the volume of pollen and nectar even a short length will produce, as opposed to individual plants in a garden. The mix of species also ensures a long flowering period – there’s rarely a time when something isn’t in bloom. Hereabouts it’s the Blackthorn blossom in early spring which saves the honey bees from starving, and at the end of the season the ivy in autumn lets them stock up for winter on warm autumn days. Different flowers attract different pollinators, so a mixed native hedge will support a whole range of them.
Plants like blackthorn and hawthorn provide fantastic shelter for invertebrates, small mammals and birds. Hedges are handy corridors for wildlife too, and offer relative safety for animals while they move about. One of the issues exercising the conservation lobby at the moment is the fragmentation of good quality habitat, which need to be joined up. Hedges can be a pretty good way to do it, at least on a small scale. Animals don’t just use them as “wildways”, but also as navigation features. Bats use them to find their way across the landscape, for example, and bumblebees fly along them too.
Starting a Hedge
It couldn’t be easier to start a native hedge – after all, these are our British plants, so it should be easy to grow them! Before you start, prepare the ground by weeding a strip about a metre wide. If you have livestock, think about whether it would be best to wire the hedgeline before or after you plant your new whips. Don’t under-estimate the width your hedge will grow to.
Find a good quality supplier of British plants. There are plenty online, but do look carefully – please source your plants from a British nursery. Some of the large scale hedge renovation over the last 30 years has used plants from all over Eastern and Western Europe. There are lots of reasons to use hedge plants with British provenance, not least biosecurity. Some suppliers are either coy about provenance or infer it, so ask.
You’ll need 5 plants per linear metre to create a stockproof staggered double thickness hedge. We usually recommend something like 50cm between rows. That’s not to say your hedge must look like that. You might not have enough room for two rows of plants, for example, although the thicker the hedge the better from the point of view of wildlife. Some folk want a really thick, triple thickness hedge (7 plants a metre). If you wanted something optimal for a “wildway” you could plant rows up to 1m apart.
Many woodland nurseries sell a “conservation hedge mix”, or “mixed traditional” or “country” hedge mix, which should be a good diverse default mix for the agnostic, and will qualify for grants. It’s suitable for a wide range of situations and soils and consists of species widespread across the UK. If there are plants in it you don’t want or plants you particularly do, the nursery will usually happily tweak it for you. We don’t suggest using Blackthorn in a hedge next to a lawn, for example, because it suckers freely. On the other hand, you do want some suckering species, like dogwood and hazel, to help thicken up the hedge. You may also have a particular soil type or site which suits some species more than others.
Most farmers buy the smallest size plant on offer, which is often 40-60cm. Unless your site is very exposed, personally I’d stretch to the next one up, 60-90cm, which is the size we used in the picture. They’re still pretty small whips, which are easily planted and quick to establish. There is no point buying anything bigger as you’ll end up with a hedge with no bottom.
The whips will be bare root as they’re much easier to transport and will take much better than pot grown. They’re consequently delivered from November until the end of March while they are dormant. They should arrive in special packaging, so will sit in the shed/garage quite happily for several days. If you’re not planting them for a longer period, heel them in somewhere.
When you do get around to planting your whips the key thing is to keep the wind drying their roots out. I march around with the whips in a bucket of water. We tend to use Rootgrow now too, which encourages rapid establishment. The other big issue is frost; don’t try sticking them into frozen ground. They’re easy to plant, particularly if you have a two person planting team. One of you needs to open a slit in the ground with a spade and the other just pops a whip in and treads around it. Snip a few inches off the top of the whip to encourage the development of lateral branches.
If you have rabbits or deer you will also need the ubiquitous plastic spiral and cane. These will also help support and generally protect the young hedge plants, particularly against strimmers, rabbits and voles. The wretched things aren’t biodegradable, however, so if you can fence in your hedge instead that’s a better option.
First off, you MUST keep the base of your native hedge clear of weeds and grass. The whips don’t need to compete with perennial weeds while they are getting established. If you don’t use a mulch then you’ll have to weed for a couple of years. WE don’t recommend using strips of plastic mulch as the voles love to hide under them and eat your new plants’ roots!
Once established – after a couple of years – removed hedge guards and canes if you have used them.
Without plant management, in a few years’ time you’ll have a different problem to deal with. Although we’ve pretty much arrested the decline in the length of hedges in the UK, they’re beginning to turn into rows of small trees. Left unattended your native hedge will go vertical, which is less helpful for all than a dense hedge with a wide base.
As time goes on the ideal way to ensure a perfect hedge is to lay it, but that’s often not practical. That’s a whole different blog anyway! Establish a trimming regime that impacts the least on local wildlife, though. The Single Payment scheme asks for hedge cutting to stop between 1st March and 31st July, but the optimal time to do it is January and February. That’s after the berries have been eaten but before birds start nesting.
Don’t butcher a hedge to an inch of its life, as you often see flails do, but trim it in a two or three year rotation to let it fill out. The Single Payment scheme quite sensibly specifies a 2m wide uncultivated zone from the middle of the hedge.
If you do need to take extreme action to get a mature hedge back under control, coppice it in sections, year by year, to minimize the impact on wildlife. Ideally, gap up a hedge while renovating it with locally sourced whips in keeping with the species you see around you.