A couple of decades ago a magic formula was discovered: the age of a great British landmark, the countryside boundary hedge, could be determined simply and easily by counting the number of species in it. The rule of thumb was that each extra species meant an extra hundred years of age, the formula for those of a mathematical bent was:
Age of hedge = (99 x number of species) – 16.

Terribly neat, and of course far too neat for reality. As its creator, Max Hooper of the Monk’s Wood Experimental Station (later Institute of Terrestrial Ecology) in Huntingdonshire, himself said, this could only be speculative, and should be considered with a host of other factors. I was reading about the theory in Hedgerow History: Ecology, History and Landscape Character by Gerry Barnes and Tom Williamson. This is on one level is a classic piece of revisionist history; their detailed study of Norfolk hedges demonstrating that soil type, salt levels, the presence or absence of nearby relic woodlands and a host of other factors have as much to do with species number as age.

Unlike some revisionist history this is clearly a necessary corrective, and a fascinating one even to the total beginner to the subject such as myself; hedge history wasn’t a big part of the Australian history curriculum. Consequently I found the introductory chapters fascinating, learning from them about the making of hedges (a lot more complicated than just putting in a lot of plants close together), the history of enclosure of England (which started long before the formal parliamentary period in the 18th and 19th centuries), and about the ecology of the hedge.

First of all, what is a hedge? Historically it meant any form of enclosure or fence, including an earth bank or “dead hedge”, lines of brushwood staked for form a barrier. But a live hedge is what we most commonly mean by the term today, and that is something that requires more than the odd trim. The main management is by “laying” or “plashing”:

“The hedge is first hacked back rigorously with a billhook and any lateral suckers removed. So too is dead material and any unwanted species – those which might harbour pests (such as barberry) or which provide a poor barrier to stock (such as elder). Next, the principal stems are cut roughly three-quarters of the way through, at an angle between 45 and 60 degrees and at a height of between five and ten centimetres aboce ground level: they are then bent downwards at an angle of 60 degrees or more so that each ‘pleacher’ (as the principal stems are usually called) overlaps its neightbour. In the spring, when growth resumes, a thick impenetrable wall of vegetation is created. (p. 2)

Hedges were traditionally accompanied by ditches in many areas, making them more of a stock barrier and also, importantly, on heavy land helping to drain the adjacent fields, usually being connected in a complex network to natural watercourses. “The soil dug out of the ditch was usually dumped on the adjacent hedge bank: this explains the traditional legal position regarding the line of rural property boundaries, which are deemed to run not along the line of the hedge itself, but along the further side of the ditch.” (p.5) (No wonder British property law is so complicated.)

Landscape historians, after the historical ecologist Oliver Rackham, tend to refer to “ancient” and “planned” countryside. The former he described as “The land of hamlets, of medieval farms in hollows of the hills, of lonely moats in the clay-lands, or immense mileages of quiet minor roads, hollow-ways, and intricate footpaths; or irregular-shaped groves and thick hedges colourful with maple, dogwood, and spindle”. This is mainly found in the west, in the south-east and southern East Anglia, in the West country and the Marcher counties. Planned countryside by contrast is marked by big villages, few roads, thin hawthorn hedges, and ivied clumps of trees in the corner of fields. It is concentrated in the Midlands, in a broad band from Northumberland to the south coast.

Hedgerow History explains that this division emerged in this way after about 1650, but has much earlier roots. Writers of that time already spoke of what they called “woodland” and “champion” countryside, the former having land already divided by hedges, settlement was scattered, sometimes without any villages, and there were lots of areas of managed woodland. “Champion” countryside retained older characteristics, with largely unhedged, small strips of land forming great open stretches of land. These had come into existence in Saxon times – although each farmer owned their own strips, the village would combine for the heavier tasks such as ploughing.

The “champion” countryside could be further divided into that found in the clays of Middle England, an intensive arable area by the 13th century, while on the lighter soils of the heaths, wolds and downs, large areas of grazing survived since the thin, easily-leached soils could only be kept fertile by the input of large quantities of dung, so great flocks of sheep were grazed on the fallow and pasture during the day, and at night folded on the arable. These were known as the great “sheep-corn” districts.

“Piecemeal enclosure” was a gradual process that began at least at the start of the millennium, and speeded up greatly from about the 16th century, and involved private exchanges that led to the amalgamation of smaller strips of land that were then hedged or walled. There are few written records of it, but it is clear in the landscape, for it tended to preserve the old strip layout in a modified form, and these were seldom dead straight, rather have sinous forms reflecting generations of ploughmen gradually adapting their furrows to the lie of the land and often with a shallow reversed “S” caused by the way a ploughman had to move to the left as he approached a headland to avoid too tight a turning circle. Also there are often small doglegs or kinks, and the boundary of each field frequently runs not to the corner, but some point further along, a strip or two away.

General enclosure by contrast involved a whole community of proprietors acting in concert and tended to produce regular rectilinear landscapes, and long straight stretches of hedge. There was a frenzy of parliamentary enclosure during the Napoleonic Wars, at a time when grain prices were abnormally high.

But the two were not mutually exclusive, in the late 18th and 19th centuries many of the earlier irregular enclosures came under attack, and the older hedges, planted with an eye to fuel, timber and even food supplies (fruit and nuts) were regarded as too large, invasive and difficult. In the 18th century there had been a great proliferation of commercial nurseries that meant the primary plants of the time – hawthorn and blackthorn – became widely available.

As I go on countryside cycling trips in future I’ll be looking at the roadsides with new eyes, not just wondering about what it will be like if I have to throw myself into the hedge to avoid a rogue driver. And the nice range of colour pictures here will have greatly improved my plant identification.