Leaves can supply all the colour a garden needs, and can make it look attractive all the year round. They can also be used as a background or as a complement to flowers, and striking effects can be achieved with their special qualities of texture, shape and size. Such colours as bronze, purple, gold and silver in varying shades can be brought to the garden by. Another great virtue of foliage is that its colour usually lasts much longer than that of flowers, and, if a good selection of evergreen is used, the effect can last throughout the winter months.
Plants grown for foliage can range in size from the 100ft. high golden-leaved poplar (Populus serotina aurea) to the little golden creeping Jenny which can bring sunshine to a dark corner at the bottom of a wall. The crimson-leaved vine (Vitis vinifera purpurea) climbing up a light stone wall is just as effective as a massive copper beech (Fagus sylvatica cuprea) silhouetted against the sky.
Texture variations can be as telling as colour combinations. The soft woolly leaves of Ballota pseudodictamnus are in great contrast to the large shining leaves of the bergenias, and the smooth waxy leaves ofspectabile need the relief of something light and dainty such as Alchemilla alpina, with its silver-edged leaves. Shapes of plants are important too. The coloured-leaved sages (Salvia officinalis purpurascens and S.o. icterina) make rounded hummocks of purple or gold, and they are good foils for the towering cardoon (Cynara cardunculus) or slightly smaller globe artichoke (C. scolymus).
A golden-leaved shrub is often as colourful as a plant with golden flowers. A single specimen of the golden privet (aureo-marginatum) trained against a house wall provides brilliant colour in the winter and from the distance looks like a golden-flowered jasmine. pungens variegata brings sunshine to a dark corner and the golden macrocarpa grown in a prominent position is a most cheerful sight in the dark days of winter. The little golden nitida Baggeson’s Gold grows so slowly that it is not too big for a large and makes a pleasant informal shape. Gold and green are a pleasant combination and in a herb garden golden marjoram (Origanum vulgare aureum) grown inside small box hedges is very beautiful, particularly in the summer when the marjoram is the same height as the box. Crimson and silver can make a most striking picture and there are many ways of growing them together. The crimson-leaved bugle (Ajuga reptans atropurpurea) makes a wonderful carpet round the silver-leaved Senecio laxifolius or S. greyii and soon grows so densely that no can penetrate. The purple rhus (Rhus cotinus foliis purpureis) with its clouds of tiny purple flowers combines well with Artemisia stelleriana, with its rather large silver leaves; the purple-leaved berberis ( thunbergii atropurpurea) needs a light and feathery silver plant—Artemisia absinthium Lambrook Silver or the lacy Senecio leucostachys make good companions. The purple phormium (Phormium tenax purpureum) is such a handsome plant that it needs to stand alone, but a silver carpet is attractive. For this Stachys lanata can be used, but all the flower spikes should be kept cut; nothing should complicate the clean lines of the phormium.
For the front of a border, several foliage plants of about the same height, planted together so that the colours are blended, make an original and pleasing scheme. The glaucous-leaved Othonnopsis cheirifolia never grows more than about a foot high and it spreads byitself to the ground. Its small, yellow daisy flowers are quite pleasant and go well with the small, ivory flowers of Anaphalis triplinervis, which makes a silver rosette. A mound of golden sage (Salvia officinalis icterina aurea) that is not allowed to get too big, a small bushy plant of Rata graveolens Jackman’s Blue, with its blue leaves, and the soft, green, folded leaves of Alchemilla mollis complete a satisfying arrangement.
Different coloured leaves ascan lighten a dark corner of the garden or bring interest to a planting of shrubs after the flowers are over. The variegated mints, Mentha rotundifolia variegata, with white variegations on pale green leaves, and the golden ginger mint, M. gentilis aurea, increase quite quicksand should be kept low by cutting off flower stems, while the variegated form of Veronica gentianoides has bright silver edgings to its shiny, dark leaves and makes a dense, flat carpet.
Planting round a house needs to be permanent and great care should be taken to choose plants whose foliage will blend with the colour of the house walls. Against red brick particular care must be taken, and the tough, silver-leaved shrub Senecio laxifolius is a good choice, but it may be better not to allow it to open its bright yellow flowers. Atriplex halimus is another good choice, orhorizontalis could be used. Between taller plants, the low-growing glaucous hebe ( pageana) could be planted to spill over the path, or the incense-scented H. cupressoides used against the house. Most foliage shows up well against stone and the bright bronze of Cassinia fulvida is effective. Coronilla glauca can be trained against a house wall and will produce its yellow pea-like flowers in winter, and Hebe colensoi glauca makes an attractive small shrub for such a position. Tamarisk is lovely against a white wall.
Some of the plants grown for foliage are worthy of key positions in the garden. The weeping pear (Pyrus salicifolia pendula) is excellent as a specimen tree, and the towering cotton thistle (Onopordon arabicum) looks best against a dark background, such as a yew hedge. The euphorbias are beautiful all the time and produce their great heads of love-bird green flowers very early in the year; they show up best on paved terraces or courtyards, in important corners, or at the foot of a wall or steps, where they have the scene to themselves. They will grow in sun or shade and in anythat is not too rich.
Variegated shrubs give great relief among darker foliage, and a small variegated plant, such as variegated rue, can be almost as colourful as a clump of deep cream flowers. As a general rule plants with silver variegated foliage do best in shade, and those with golden variegations are usually brighter in full sun.
When planting for foliage effect, it is best to put the evergreen plants in places where they will be seen most, and the plants that lose their leaves in less conspicuous spots. The hostas have leaves as beautiful as any in the garden and they are lovely throughout the summer; but they are not attractive when they die off in autumn, and disappear completely in winter. Hostas therefore need a position where their decaying is not conspicuous. The same thing applies to shrubs that lose their leaves, and to rather tender plants that may not survive the winter.
Great use can be made of foliage plants as a background for other things. If spaces are left for, for instance, among permanent plants with good leaves, the whole effect is more pleasing and it will not matter too much if the annual plants are not a success. Some flowers look best when grown by themselves, but there are very few that are not more beautiful with a complement of really lovely leaves.