The Herald - The Herald Magazine
Hedging Even a modest planting can lure foot soldiers in the war against pests
HEDGES are a haven for wildlife, providing irresistible supplies of food and shelter. They harbour a diversity of species from tiny organisms to insects, spiders, birds and larger mammals such as hedgehogs. Well-established rural hedges comprise a mix of several native trees, including hawthorn, blackthorn, hazel and holly. People have been managing hedges like this for millenia. Excavations near Peterborough have identified the remains of a blackthorn bush that had probably been pruned like a hedge between 4,000 and 5,000 years ago.
These native tree species have allowed a complex web of interdependent, sometimes invisible communities to evolve. For example it’s known that ants feed on the honeydew of the jumping plant louse, which feeds on hawthorn. In turn, a tiny, parasitic wasp, Prionometus nitratus, feeds on the louse’s larvae. This wasp then provides a meal for another wasp, P muscarum. Sadly, though, the ant comes along and devours P muscarum, which gives P nitratus a free hand to consume the louse larvae.
The keen-eyed observer should get a glimpse of many other inhabitants of an established hedge, including greenflyconsuming lacewing. Throughout the year, two or three generations of their voracious larvae work in and around a hedge.
Birds are the easiest to see. Great tits are invaluable as they need as many as 1,000 caterpillars to raise a brood. Chaffinches also use hedges, feeding largely on seeds during autumn and early winter, though they hoover up invertebrates, larvae and spiders to feed their chicks.
Very few of us could have as large a hedge as those you see in classic country lanes. With a medium-sized garden, however, the concept could be adapted. It would be difficult to have one as a boundary with neighbours – they might not appreciate its shade, width or root spread – but a hedge planted well inside your garden space might be possible. And a 1m-2m wide hedge would be more useful to wildlife when the bottom is widened with a verge containing wild flowers and tussocky grasses.
Planting slightly shady corners is often difficult, but soften these rectangular areas by allowing shrubby hedging to fill the corners. This way, you are creating short but much wider hedging “pockets” linked by narrower hedge. If you already have a hedged corner, prune the bushes to allow the hawthorn or holly to spread inwards.
Native species of shrubs and trees grown from local seed are better adapted to local conditions, which also affect the behaviour of wildlife. Great tits, for example, time their hatchings to tree bud burst and the large increase in larvae that follows on.
This is borne out by the research platform Fundiv Europe, whose Europe-wide study shows trees from locally produced seed grow much more strongly than seed from other parts of the Continent.
During the 18th-century enclosures, hedging plants were produced in the tens of thousands from locally sourced seed. Back in 1768, one nurseryman advertised half a million two-year-old hawthorns for sale at the knock-down price of four shillings per thousand. In contrast many species native to the UK aren’t necessarily grown from British seed now. A recent paper found 80 per cent of hawthorn grown in the UK came from as far away as Hungary.
Try to track down ones that are grown from local seed. One firm, Taynuilt Trees, collects seed from around their nursery in Argyll. As the owner, Peter McCracken tells me: “It’s really satisfying to see a hedge flowering at the right time and providing a fantastic habitat for insects and bird life.” Visit rspb.org.uk