Hedging your bets

Hedges are a living, self-sustaining form of land enclosure, boundary or marker, synonymous with the British landscape, and one of the few human interventions nature approves of. Mostly brought in after the majority of our large native wildlife had died out, they only impeded stock, as intended, whilst for the rest of our flora and fauna they provided much needed surrogate scrub and woodland habitat around cleared agricultural land.

In the last 70 years, we have lost 50% of our hedgerows in the UK in a drive for larger fields, greater yields and urban development. This, along with a widespread loss of hedge management wisdom has driven down farmland and woodland bird, butterfly and mammal numbers.

So why are hedges so important? What makes so many species dependent upon them? Well there are several answers, each tied into the others.

Firstly, they form a unique habitat in their own right, that is part woodland, part grassland and part scrub, and complementary to nearby pockets of each of those individual habitats themselves, whilst supporting many species that depend upon those habitats. This support may take the form of home, temporary shelter, food bank or travel corridor. And what's more, most of our wildlife has evolved alongside it's availability for the last few thousand years.

Next, this supporting role has become evermore vital, as our agriculture, forestry and development becomes increasingly intensive, eroding the few remaining untidy patches of available woodland, grassland and especially scrub, year on year. So, if you are a developer, how amazing would it be to leave hedges in situ? How much richer would life be for the people living or working thereafter?

And hedges make themselves even more indispensable through their associated habitats like hedgerow trees, diverse field layers, leaf litter and streams or ponds.

All these properties give your average hedgerow many uses. They provide shelter and shade to stock and wildlife alike. They shelter crops, prevent soil erosion, pollution and flooding. They tie up carbon, aid pollinators and host pest control species of bird and invertebrate. Hedges are many things to many species, including us.

The bulk of a hedge is usually formed by the shrub layer which often comprises classic scrub species. These can be blackthorn, hawthorn, holly, elder, ivy, rose, honeysuckle, dogwood, buckthorn, hazel or willow, and may have a smattering of tree species mixed in, such as oak, ash, elm or lime. Whilst below and along the margins grow grasses and forbs like campion, bluebells, ransoms and hedge parsley. Many of these diverse species are renowned for their flowering or fruiting, which makes them so special to birds and pollinators. The more diverse the hedge, the more variety of fruiting and flowering times available, hence the more species are supported in turn. However, many urban and garden hedges use non-native species like laurel or privet that are far less supportive to wildlife.

If you are lucky enough to be responsible for one or more hedges on your land, I would strongly urge you to carefully consider their management. If you are on a rewilding trajectory, I appreciate this may seem at odds with your normal passive approach to recovery, and that examples like Knepp's massive overgrown hedges may make you unsure which direction to take. Perhaps you could try a combination of managed and unmanaged hedges, maybe that would be a compromise. But if there was one aspect of your venture where I would advocate more active management, certainly your boundary and corridor hedges would be it.

Why? Well as previously mentioned our wildlife is pretty habituated to traditional hedgerows, with the dense cover, fruit and flowers, and broad-crowned trees that such management endows them with. Without such management hedges grow leggy and gappy, often pulling their bounty up out of reach of some animals, and eventually form tree lines. It is true that during transition, they may form wonderful scrub tunnels, habitats in their own right, as at Knepp, and possibly the source of their nightingale numbers. However, whilst both types of hedge have their benefits, you wouldn't want to lose all those dense, food rich, secret corridors that typify a hedge everywhere, would you? On the whole, managed hedges have greater species diversity, and denser cover, so they will better support migration both to/from your site and across your site. Therefore, by managing your boundary hedges you support connectivity to your neighbours, and by managing internal hedges in more open areas, you better support species being able to move around your site.

On the other hand, nature managed before hedges, and undoubtedly will again. Although remember, nature managed when it had the freedom of hundreds or thousands of square miles, and unfortunately you don't have that scale of gift in your power, so interventions like hedge management may enable your plot to support more species at a realistic scale. To reiterate, the decision rests with you.

So how do you traditionally manage a hedge. Well the key is to create an "A" shaped profile with a slightly broader - not pointy - top. So the sides slope gently out towards the ground. Then each cut comes out about 10-20 centimetres, or at least past the next bud from the previous cut. That way you always get fruit and flowers on your hedge. Usually you cut hedges on a 3-5 year rotation for best results, and if you have different sections of hedge on different stages of that rotation then you only need to cut a bit of hedge each year.

Whilst cutting, try to protect the field layer, which can be an important habitat in its own right, sometimes containing ancient seed banks. And if flailing please be gentle around hedgerow trees. These specimens often grow to be amongst our best veteran trees, because they get plenty of light and space for their crown to fill out. It's worth remembering to mark out some future trees amongst the hedge denizens too, so that you have a progression of trees every twenty to forty metres. All too often, old trees stand out lonely in the hedge, with no young pretenders in sight.

The best time to cut hedges is around October to January - earlier will protect ground from being damaged by machinery, whilst later will ensure as many berries help overwintering birds and mammals as possible. Naturally, leave it too late and you risk disturbing nesting birds, which is a legal issue as well as an ecological one.

To repair a hedge that has been damaged by under or over management, either consider relaying it or replanting in the gaps. Try to use a variety of native species, preferably ones that support many other species, and that fruit and flower at varied times. Some of the richest tree species for wildlife are oak, birch, willow, hawthorn, apple, crabapple, pear and plum. Whilst ivy, rose, honeysuckle, hazel, dogwood, blackthorn and bramble are fabulous shrubs. In gardens where a future oak tree may be a step too far, maybe consider hawthorn and fruit trees that are easier to commit to.

Finally to make your hedge immortal, every few cuts you will want to relay the hedge, or coppice it. This allows your hedge to fill out at ground level again, enabling the cycle to start all over again, and prevent it from becoming an avenue of trees. In such a traditional manner, some British hedges have carried on for hundreds, possibly thousands of years. In many ways they are living, thriving, beautiful, historic monuments.

To find out more, why not visit https://hedgelink.org.uk/hedgerows/hedgerowbiodiversity/