Topiary: we're all going bonkers about box Harriet had always loved topiary. Brought up at Holker Hall in Cumbria, she and her siblings were often invited over to play at nearby Levens Hall, with its famous topiary garden. I always loved the yews. They were exciting, quite spooky. Holker then wasn't the formal garden it is now, so it was at Levens that the fascination began. The Sykes's Gothick castle in Dorset Later, making her first garden in London, she began to grow and train her own topiary, blending Italianate formality with frothy Verey-style borders. Today she works with yew and hawthorn, Portuguese laurel (Prunus lusitanica) and Japanese holly (Ilex crenata), but box remains her favourite. It's just so multi-purpose. It's a plant of grand gardens, but also of cottage gardens. You can use it in the smallest space - even in a tiny front garden no bigger than a table you can make a little parterre that's lovely to look out on. It's perfect for adding height and structure - there's nothing like a lovely big pyramid sticking up on a flat lawn, particularly in winter. And there's something terribly pleasing about regular shapes, especially where you have wilder planting beyond; the contrast is fantastic. Box makes a statement without having to do much: just trim twice a year and keep it weeded. It's a bit of a lazy gardener's plant. This, no doubt, is what makes box so popular with show home developers and city dwellers - there is scarce a balcony or front door anywhere that cannot be improved by a box ball in a pot. But what about box blight, the pernicious and apparently incurable disease that is causing gardeners throughout the land to tear up their parterres? "I believe," says Harriet levelly, "that there is absolutely no need to panic." Harriet has observed that it is plants that are under stress - too wet or too dry, overshadowed, or dripped on by overhanging trees - that tend to fall prey to the fungus (Cylindrocladium buxicola). The first defence, then, is to give them comfortable growing conditions. Then, for the past year, she has been spraying with Actiferm, an organic dilution of sugar syrup infused with beneficial microorganisms. Already we are seeing terrific benefit. It produces good bacteria to fight the fungus, and also feeds the plant and improves the soil - essentially it's good microbes fighting the bad. Harriet Sykes and her husband, Anthony We also sprinkle bokashi ash into a thick mulch to encourage a healthy ecosystem around the roots. The old chemical sprays are rather like a course of antibiotics that you can never finish - they suppress the disease, and it looks fine for a bit, but eventually it comes back. With this treatment, the plants are steadily building up resistance. Diseased box looks absolutely awful - but give it time and it will regenerate. So my advice is not to rip it all out and burn it. Keep it clean, keep it clear, cut out any dead branches and it will come back. How to fight the blight Much research is going on into developing blight-resistant strains of box. Harriet is yet to be convinced that much-vaunted varieties such as Buxus microphylla "Faulkner" or B. microphylla "Trompenburg" perform substantially better than common box (Buxus sempervirens), though she no longer offers the notoriously vulnerable variety "Suffruticosa." To her mind, the key to avoiding disease is strict hygiene and careful husbandry. Harriet's tips for avoiding box blight: Avoid sites that are excessively dry, waterlogged or deeply shaded. On heavy soils, dig in plenty of organic material to aid drainage. If growing in containers, make sure plants are regularly watered - especially in early spring, when winds can rapidly dry the pots but because it is not yet warm, you're not thinking about watering. Water more sparingly in the winter. Feed well - a healthy plant is much less susceptible. Add blood fish and bone when planting, then top up with a slow-release fertiliser such as Osmocote three times a year. A regular spray with Actiferm will aid resistance, and is especially important after clipping. Try to keep a good flow of air around your plants. Carefully snip out some of the branches in the middle - not so it shows on the outside, but just to keep the air circulating within. Scoop out any dead leaves. Clipping exposes the plant to infection, so don't overdo it. Clip first after the last frosts but before it gets too hot, choosing a moist, dull day - never in hot sun. Then a tidy-up towards the end of October will see the plant through the winter, ready to go in the spring. Rather than clipping perfectly flat, cut to a shallow curve - the flat tops of cubes and hedges seem especially prone to infection. Always clear up and burn all your clippings. In an ideal world, put down a mat when you're snipping. Otherwise, be conscientious in raking up debris. The spores live on dead wet leaves so, when it rains, the spores are thrown up back into the plant. Don't let herbaceous planting droop on to your box - it will create a warm, moist trap that is ideal for blight. Bellamont Topiary, Long Bredy, Dorset (01308 482690; bellamont-topiary.co.uk).