How to Maintain Hedges: PARASITES, PESTS AND OTHER PROBLEMS

All living things – fauna, flora and fungi – are attacked by other living things ranging in size and complexity from a microscopic virus to a hungry deer. Let’s face it – Homo sapiens is hardly immune from disease and put two Rose growers together in the same room and the first thing they’ll talk about will be Black Spot and other afflictions…
Hedging plants are therefore no exception and so, while they are among the hardiest and healthiest of plants (even Box Blight, as we have seen, is not inevitably fatal), there are potential problems to keep an eye out for. The danger, though, of a post like this – I’m about to list the most common of these potential threats to popular hedging plants – is that it can give the impression that hedging plants are doomed to an early demise. This, of course, is not the case – just because a disease might strike certainly doesn’t mean that it will, but forewarned is forearmed…
Beech (Common and Purple Coppe)r: Aphids, Beech bark scale, coral spot and bark stripping by grey squirrels. Mature trees may succumb to heart and root rot
Common Box: Box sucker, mussel scale, box red spider mite leaf spot and box blight
Escallonia Macrantha: Generally pest and disease free though can suffer from Escallonia leaf spot
Euonymus fortunei ‘Emerald ‘n’ Gold’: Vine weevil, horse chestnut scale, caterpillars, leaf spot and powdery mildew
Griselinia Littoralis: Generally pest free but leaf spot can occur
Hornbeam: Caterpillars, aphids, powdery mildews and coral spot
Cherry Laurel: Vine weevil, leaf-mining moths and powdery mildews
Lavenders: Leafhoppers, Rosemary leaf beetle and grey moulds
Leylandii: Conifer aphids, scale insects and canker
Lonicera Nitida: Generally pest free but powdery mildew can occur
Perovskia Blue Spire: Generally pest and disease free
Photinia Red Robin: Vine weevil, fireblight and leaf spot
Privet: Aphids, leaf-mining moths, thrips and leaf spot
Rosemary ‘Miss Jessopp’s Upright’: Generally disease free but brown scale and rosemary leaf beetle may be found
Yew: Tortrix moth, vine weevil, gall mites, scale insects and phytophthora root diseases
Some of these problems are really of no consequence. Leafhoppers (Cuckoo Spit), for example, are easily dispatched by a quick burst from a hose. Others – I’m thinking in particular of leaf spot, coral spot, powdery mildew vine weevil and aphids – are common irritants to most (or even every) garden, whether they enjoy a hedge or not. We’ll look at all of them in turn in our next posts…
NB: And on the up side, established hedging plants are all but untouchable by the perennial number one in the RHS’ annual Top Ten of garden pests – slugs and snails.