Everything's all white in the garden for Troy Scott Smith.

Back in 2002, I was commissioned by the Royal Botanic Gardens, Kew, to design a planting scheme based on colour theory. With my design partner, I conceived a flower shape, covering a circular space of about 75 yards across. It resembled a colour wheel, made up of three sets of three beds (the ‘petals’) with the central bed in each case planted in a primary colour and a gradual succession of colour pigments in the other beds. These separate waves of pigment were engineered to take the visitor on a journey through angry tangles of hot carmine reds and cool shades of ultramarine, cobalt and indigo.

Since then, I’ve been fascinated by how we employ colour in our gardens for many of us, using colour is one of the few opportunities we have to express ourselves. At Sissinghurst, the first thing that strikes a summer visitor is the sheer range of colour that Vita Sackville-West used in her garden, from the vibrant sunset hues of the Cottage Garden to the rich plums in her Purple Border. Vita’s palette was sophisticated, using colour in new and exciting ways.

Contrary to what might be supposed, gardening with colour is not about individual plants, but, rather, how best to combine plants of different colours. The colour wheel usefully provides a way of understanding colour harmony and contrast which colours are close to one another and which are discordant because they’re physically opposite each other. I find it best to do it physically, arranging plants side by side, rather than in my head.

Vita’s most dramatic use of colour at Sissinghurst can be found in her legendary White Garden. It’s an essay in the use of flowers, foliage and fragrance within the limited palette of white, silver and green. Although it was by no means the first of its kind, it was rare enough at the time. Made in the early 1950s, it represents the plantsmanship of Vita at its most highly developed stage; her White Garden was to become one of the most celebrated and influential garden set pieces of the 20th century.

A blanc canvas

In the White Garden, without the immediate attraction of a mixture of colours, our attention is drawn to texture, form and shape. The symphonic planting is a composition in the use of only white flowers and the interplay of leaves, in shades of green and silver. Contrasts in foliage and flower shape are vital. The tall, tapering spires of Eremurus and Digitalis, for example, are juxtaposed with mounds of Paeonia. Crambe cordifolia, whose cage of flowers froths like a billowing cumulus cloud, acts as a convenient peg for later-flowering clematis.

Writing about her White Garden, Vita said: ‘The white-and-grey garden begins to look well in June, when the little avenue of Almond trees down the centre is draped with the lacy white festoons of Rosa filipes and the genuine old “Garland” rose, and when generous plantings of Lilium regale come up through the grey Artemisia and silvery Cineraria maritima; but it is perhaps at its best a little later on, when the great metallic-looking Onopordons have grown up, and clouds of Gypsophila “Bristol Fairy” throw a veil round the pencils of a white Veronica, and a few belated white Delphiniums and white Eremuri persist, rising among this grey foliage, with the grey willow-leaved Pyrus salicifolia sheltering the grey leaden statue of a Vestal Virgin.’

Vita and her husband, Harold, would dine there in the evening, so the planting in the White Garden is just as dramatic at night. Whereas red and blue sink into shadow as day fades to night, white prolongs the summer evenings and the silver-grey foliage takes on a remarkable, luminous quality.

Most gardeners feel relaxed about white as they think it’s an easy colour to use, but, in fact, it’s one of the most difficult. But when it’s used with skill and imagination, as Vita showed at Sissinghurst, it is truly inspiring.