The single biggest improvement you can make is to plant more rich-green evergreens with high-gloss leaves. These shine out like a beacon in winter light and radiate warmth just when we gardeners need it most. You can use them informally by planting evergreen shrubs, or you can topiarise yew and box. Tightly-clipped evergreens, such as yew and box, will add formal structure as well as warmth. They look particularly stylish in town gardens.
Box (Buxus sempervirens ‘Suffruticosa’) can be clipped into any shape due to its small leaves. Spirals, cones, balls and squares are more traditional. But I have a handsome cockerel and a hen! The traditional time to clip box is early June, after the frosts have ceased. If the shape needs more honing, give it a second light trim in late August. Yew is clipped in August and is a much larger plant suitable for hedges or larger single specimens
Both are best grown in the ground and both will benefit from a controlled release fertiliser used in the growing season - between April and September. You can containerise box. But it will need regular watering and a fortnightly nitrogen-rich feed to keep the foliage a rich green.
Some evergreens will also provide winter fragrant flower as well as good leaf and the best of all is Sarcococca confusa. This oriental, small shrub has rich-green pointed leaves and ivory white flowers which are little more than collections of stamens. But they belt out a powerful scent which will fragrance a wide area so use it close to gates, doorways and paths. This shrub is also very happy in a container.
There are lots of skimmias that you could use too, but the star performer is Skimmia x confusa ‘Kew Green’ -a small laurel-like shrub which produces sweetly fragrant cream flowers in spring. Skimmias are tremendous garden value, because they produce their buds in the previous summer. ‘Kew Green’ has triangular heads consisting of hundreds of lime-green buds suffused in rhubarb pink. These are every bit as decorative as the flowers and they give a long season of interest before the flowers open. Some female skimmias also berry well and the best is S. japonica ‘Nymans’.
If you need a larger winter-flowering evergreen for the edge of a garden, forms of Viburnum tinus are ideal. They have the added advantage of being able to grow happily in deep shade. Although the clusters of flowers aren’t fragrant the combination of pink bud against white flower is delicately pretty in winter light. ‘Eve Price’ is the most compact and colourful - the dark, almost-red buds frame pink flowers. ‘Gwenllian’ is larger (up to 10 ft or 3 metres) with paler blush-white flowers.
You can also explore hollies, eleagnus, aucubas, choisya, osmanthus and photinia. But opt rich-green leaved varieties rather than the golden variegated ones if you want to get the ‘winter warmer’ effect.