May: Reading The Hedgerow
Reading a Hedgerow
A hedgerow in May is one of the most information-dense things in the British countryside. Most people walk straight past it. Here's what you're actually looking at.
There is a hedgerow near most of us. It might be at the edge of a field, along a footpath, the back of a garden, or the boundary between two farms. In May it is doing something extraordinary and almost nobody stops to look.
A mature British hedgerow is not a row of bushes. It is an ecosystem, a linear wood, a wildlife corridor, a foraging larder, a nesting site, a bat navigation route and a history book all compressed into a strip of land that might be two metres wide. The oldest hedgerows in Britain are over a thousand years old. They predate most of the villages near them.
"There is a rule of thumb used by ecologists: count the number of woody species in a 30-metre stretch of hedgerow. Each species represents roughly a hundred years of age."
What's happening in May
May is the peak month. The hawthorn is in full blossom, clouds of white flowers with a scent that is sweet and slightly animal, impossible to mistake. The blackthorn, which flowered earlier in spring, is already forming its sloes. Elder is coming into bud, a few weeks away from the flowers that will become elderflower cordial. Wild garlic may be spilling out from the base if there's any woodland nearby.
Birds are nesting in it. A hedgerow with decent cover will have whitethroats, dunnocks, blackbirds, wrens and potentially yellowhammers all within a few metres of each other. The song is dense, territorial and constant from dawn onwards.
Bats use it as a navigation corridor after dark. They follow the line of the hedge rather than crossing open space, which means a good hedgerow is worth more to local bat populations than an isolated tree or shrub.
How to read the age of a hedge
Find a 30-metre stretch of hedgerow, roughly 30 paces. Count the number of different woody species you can identify in that stretch. Hawthorn counts as one, blackthorn as one, elder as one, dog rose as one, and so on. Each distinct species represents approximately a hundred years of age.
A hedgerow with two species is probably an enclosure hedge from the 18th or 19th century. One with five or six species is likely medieval. One with eight or more may be Anglo-Saxon, a boundary that has been in the same place for over a thousand years.
This is called Hooper's Rule, after the ecologist Max Hooper who worked it out in the 1970s. It is not exact, hedgerows in wetter, richer soils accumulate species faster, but as a rough guide to the age of the land you're walking through, it is remarkable.
- Hawthorn blossom, white, heavily scented, at its peak right now. Look for the five petals and the pink stamens at the centre.
- Bird activity. Watch for birds carrying nesting material into the base. Wrens build low, blackbirds mid-height, whitethroats near the top.
- The base. Old hedgerows have a raised bank at their base, sometimes with a ditch. This is often the original boundary marker.
- Sloes forming on blackthorn. Look for small, hard, green berries where the white flowers were in March.
- Bat routes. Come back at dusk and watch the hedge line. Bats will fly along it rather than across open ground.
Why it matters
Britain has lost around half its hedgerows since the Second World War, roughly 400,000 miles of them, grubbed out to create larger fields for industrial agriculture. What's left is often poorly managed, gapped and fragmented.
A well-managed hedgerow supports more species per square metre than almost any other habitat in Britain. It stores carbon, prevents soil erosion, provides food and shelter for invertebrates that underpin entire food chains, and connects isolated patches of woodland so that animals can move between them.
None of which you need to know to enjoy one on a May morning. But it's worth knowing anyway.
"Stop at the next hedgerow you pass. Give it five minutes. You will come away knowing something you didn't before."