The first thing when designing a garden is imagining it in winter - it needs to add interest and excitement all year round! There are many plants that can do the job, the first being, obviously, evergreens! These are plants that keep their leaves all year round, the most common being conifers. One of my absolute favourites is Chamaecyparis lawsoniana, a dwarf cypress no taller than 1.5 metres, with a beautiful blue green (glaucous) sheen. An evergreen tree I love is Eucalyptus gunnii, with its silvery round leaves; another plant is Trachelospermum jasminoides, or Star Jasmine: it is green in summer and a gorgeous burgundy in winter. Recent additions to my garden are heuchera - many of these retain their gorgeous colours all winter through. Plants like Cornus alba 'Sibirica', or dogwood - in summer bearing very normal, almost nondescript pale green and white leaves, but in winter sporting splendid deep red branches. Planted against white birch trees, they look exquisite on a cold day. Don't forget structure. In winter, deciduous trees will lose their leaves, and their bare branches will look striking against the sky. But shrubs like Buxus sempervirens, or box to most of us (boxwood in the USA), especially when trimmed into a sphere or straight low hedge, will retain its green beauty throughout the year. These days, box blight is a real threat, so avoid it in your front garden where passing dogs can brush spores of blight onto your healthy hedge. Keep box in your back garden and feed it regularly to keep it strong and able to resist infection better. A good substitute for box is Ilex crenata, which looks similar, can be trimmed into shape, and is less susceptible to blight.