It is often reported that the English oak, particularly a specimen of advanced age, is host to a greater number of associated species than any other tree in Britain. Less well-known is that a wide stretch of old-established hedge can do just as good a job. The number of fellow life-forms attributed to the oak is over 2,000, the results of recent work on hedges at least matches this figure. Hedges are very much a feature of our landscape, as I have been reading recently in John Wright’s “A Natural History of the Hedgerow”. I can recommend this fascinating book which covers actual history, from the Bronze Age onwards, alongside natural history. The author defines a hedgerow as a hedge containing full-grown trees, a distinction I hadn’t thought about before.
Some creatures are so long established in hedges that they carry hedge in their names. The well-loved hedgehog is the most obvious example, but a fair few plants, hedge garlic, hedge bedstraw and hedge woundwort, all common round here, carry the name too. Burrowing animals, berry-eating and nest-building birds, sheltering toads, fluttering insects and slithering slugs and snails can easily be imagined. But to reach a count of 2,000 requires knowledge of more esoteric species such as mosses, lichens, liverworts and fungi, not to mention an entomologist’s grasp of the multitude of insect life. Who was it who said that God must be inordinately fond of beetles?
Once you start including such things as animal pests and plant diseases the number of species really racks up. Who would have thought that small rodents would have been plagued by sixteen species of flea, two flukes, seven tapeworms and nine nematodes? And I thought they just scampered about trying to avoid my cat. How interconnected life is.
Take hawthorn for instance. This is a common and traditional choice for a hedge plant, it is easily controlled and properly stock-proof. It was grown commercially on a vast scale in the eighteenth century to be used as new boundaries for parliamentary enclosure. At that time one supplier alone boasted a stock of 500,000 plants ready to be sold at 4s per thousand. Hawthorn supports nine species of rust fungus, four sorts of galls caused variously bymidges, mites and aphids, a hawthorn leaf beetle, twenty-five species of moth, a shield bug, a jumping plant louse which attacks ants that feed on hawthorn aphid honeydew (I didn’t even know there were species-specific aphids) and two parasitic wasps, one which parasitizes the louse larvae and the other, even smaller, which parasitizes the first wasp. Phew – you can see why ecologists call it a web of life.
The result of all this is that I shall view my hedge with a greater degree of respect from now on. I never realised what burgeoning activity went on behind all those prickles, I was just glad to have a few sloes to put in my gin.