"When the sun comes out randomly, it's lovely, even on a cold day, to enjoy a coffee in the sunshine. If the garden's inviting you'll go out there. That's where evergreens have real value." More Clifton clients — especially eastern Europeans and Russians, who so value out-of-season greenery — are demanding evergreens, says Wilson, because they deliver colour, form and interest right through the year.
"You can get seasonal change using bulbs, annuals and perennials, but you need that year-round structure. In a small London garden you should be looking at a high percentage of evergreens — 40 or even 50 per cent." So how do you stop the landscape looking like a series of dull green, never-changing blobs? The message is to be inventive, both with plants and planting. "Think of using more unusual evergreens, such as daisy bush Olearia, the underrated Arbutus unedo, with white, bell-shaped flowers and strawberry-like fruits, or the wonderful wall shrub Itea ilicifolia, which has amazingly long catkins.
"One of the big changes in horticulture is that increasingly the European growers are coming up with new ways of presenting evergreens. Originally a large shrubby tree, Magnolia grandiflora can now be bought with a clear stem, making it a real gem for a small space. My colleague, Maia, installed 22 clear-stemmed magnolias around three sides of a garden in Holland Park, so that all the foliage appears from the top of the fence, making a striking green screen with the bonus of perfumed flowers in spring.
"Photinia fraseri Red Robin, an ideal town garden shrub, can be bought as a standard or a pleached tree, so you can plant beneath it, grow it as a high-level hedge or as a container specimen."
Topiary, always a town stalwart, is becoming more organic. "In the past few years we've seen more of the cloud- and pad-pruned Ilex crenata, which has a darker, glossier leaf than box," says Wilson. "Just one of these large statement topiary trees — or a pad-pruned olive — will totally transform a small city courtyard."
In a small garden you need order, not chaos, points out Wilson, and evergreens score again because they're more clippable than deciduous plants. "Clients in a Chelsea garden, which is under five metres wide, wanted the garden to be as green as possible, so everything had to take to being controlled. I planted evergreen jasmine Trachelospermum jasminoides around the dining area near the house to make a green flowering hedge, clipping it close to the walls to maximise on space. In summer, it will have a mass of scented white flowers and in autumn, fantastic leaf colour."
Near the centre of the garden, on either side of the lawn, he planted a camellia hedge. "One of its advantages over yew, say, is that it has a glossy leaf that reflects light, and of course has those early flowers. It will take clipping like crazy, which also helps remove any sooty mould." Wilson reserved his trump card for the bottom of the garden, with a triple-decker evergreen hedge that provides contrasting texture and colour: a base of clipped box, about a foot high and wide, then a yew hedge behind, rising to a height of five to six feet, then above that, a third layer of pleached hornbeam, providing a fresh, lime-green leaf in spring and holding on to its dead foliage in winter.
"If you just used leylandii, it would be difficult to live with and depressing. This way, you get a lively green screen that is as dynamic as it is effective."
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