Sunday, 8 February 2015

Hedge laying

We like hedge-laying. It is such a satisfying job and the result is great to look at, and good for wildlife.

Traditionally, after the age of enclosures, hedge laying became an essential skill on the farm. Some villages like Brampton, where I live, specialised in producing blackthorn for hedging all over the East Midlands. You planted the whips quite close together, alternately, in two rows. After only a few years you had a hedge and that was why blackthorn was called "quick-set". After another few years you would have a hedge with all the growth up in the air and none at the bottom where the ground was in deep shade. Livestock could push through the hedge and get into your crops or even breed with your neighbour's pedigree herd. You needed to lay your hedge close to the ground to be a dense barrier for livestock.

From a bird's point of view, a laid thorny hedge provides a dense structure for building nests without creating tall look-out posts for predatory crows. Over time, a quickset hedge will be colonised by other species like hawthorn, hazel, field maple, sycamore etc. The mix varies regionally but most of the colonisation is aided by birds and mammals who bury or drop the seeds.

The rate of colonisation, under natural conditions, has been studied in great detail by Max Hooper and his colleagues in order to find an easy way to work out how old a hedge might be. He came up with a formula that implied that the colonisation of a 30 metre length of hedge could be defined as one species per 100 years. Obviously, you take several stretches of the same hedge and average them, but a hedge with 6 woody species of plant can be assumed to be 600 years old.

But beware! Nowadays, at least on nature reserves, we buy a hedgerow mix and plant about six species at once because we know that a more varied hedgerow is better for wildlife than a monocultural one. Think of the value of hazel-nuts, hawthorn, spindle and buckthorn berries, maple seeds and acorns to small mammals, but even more importantly, think of all the insects that live on the leaves, flowers, shoots, bark and roots of all these different species.

So we really like hedge laying. I have got so keen that I have planted and laid a hedge at home and at my son's house in London, all using the local "Northampton Style" method that uses ash for upright stakes and hazel for binding in the top. If you go to the Welsh Borders, you can see almost the same method, but the stakes will be driven in at an angle, not vertically.

One thing that is common to all of the regional versions is that the laid stems must tilt uphill, otherwise they die because the sap has to rise, drawn upwards by the transpiration of the leaves that creates a vacuum in the stem. We call this "osmosis" and it simply does not work if you lay the shrubs flat.

How do I know all this? Because, before I arrived at Paxton Pits, several of our volunteers had been trained in hedge laying, and they taught me.

One of the ring-leaders (shop-stewards?) of the midweek volunteers is Paul Davies who noticed that we had lost quite a few of those trained volunteers over the years and that we needed to train some more. He offered to run a course for us and that's how this week's course came about!

If you have a boring hedge of privet, holly or Cupressus, or if you have a wreck of a fence, I would urge you to grub it out and replant with a locally sourced native mix that you can lay in later years to provide a dense traditional hedge.