SILVER makes a real change from the more usual background green in the garden. There is a cool sophistication to which yellow foliage cannotaspire, vibrant and eyecatching though yellow and gold may beCombined with green or with flowers, a dash of silver lends enchantment to the scene, heightening and intensifying the blues, pinks, yellows and mauves of the border. In fact, silver will compliment almost any colour - too often we think of it as a foil for pink and nothing else.
Combined with red or purple foliage, it is a real success - the red of the smoke bush Cotinus coggygria `Royal Purple' near the silver of Santolina chamaecyparissus Lambrook Silver or near a weeping silver pear tree makes a simple but handsome picture.
One can get carried away with this sort of thing and try to achieve it on a large scale. In the innocence of youth and ignorance, I set my eyes on a seemingly elegant silvery tree which shimmered and quivered in every breeze.
Just the thing for a bold, silvery statement, a pleasant relief from dull greenery, I thought. Why keep that silver effect at lower shrubby or herbaceous levels when it could boldly proclaim sophistication high in the air? The wise nursery man tried in vain to persuade me that the delightful silver tree would not be suitable for a small space and could ruin the garden. I would have none of that and dismissed his cautions as bespeaking a lack of imagination and adventure.
Gardeners must be ambitious, I thought, even when dealing with a small corner. So I had my way and into an unsuitable space I put a white poplar. This is a tree I now recommend to gardeners planting an arboretum - if you have acres and acres and must have every possible tree, then do by all means plant a white poplar. It will grow 50 or more feet high. In spring and early summer the silver effect is particularly good with the upper and lower surfaces covered with white down. As summer progresses, the downy fluff wears off the upper part of the leaf and the silver gives way to dark green. Happily, the silvery white remains on the underside so that the general colouring of the tree does not change entirely. As a distant feature in your arboretum or on the edge of a field it will be very nice. It will be useful, too, by the coast as salt laden winds do not bother it. Gales on Western coasts may make this tree grow at an angle of 45 to the horizontal rather than the usual 90 but grow and survive it will. But in the average garden, avoid it.
Like other poplars, this true Populus alba sends out long roots just below ground level and they delight in sending up a forest of suckers. In grass, the constant action of the lawnmower will keep these shoots control but in cultivated ground they become a nightmare. I regularly contemplate tufts of innocent and charming looking foliage in seductive silvery hues where I do not want it at all. These emanate from the threatening White Poplar some 20 or 30 feet away and now about 30 feet high. It will have to go. Cutting it down will be easy: removing the roots which will happily regrow and colonise a wide area, eliminating a corner of the garden, will be a much more difficult and painful business.
So, silvery ambitions are better kept to a lower level. At a shrubby height of eight or 20 feet the best choice must be elaeagnus Quicksilver. This is a real pleasure and a much more telling colour in the garden than almost any of the silver leaved shrubs or small trees around. Happily, it can be trained - or pruned to form a bush or a small standard. Like the white poplar it has a tendency to sucker but this is such a desirable plant this habit will not be a source of annoyance. Instead, you will happily pot up any suckering pieces to give as welcome gifts to gardening friends who may sometimes have difficulty in locating a plant. Quicksilver is always popular, is deciduous and has sweetly scented tiny flowers in early summer.
ALMOST as nice is the silvery leaved willow Salix exigua. This can go up to 12 feet in height and has a slender habit in this garden at any rate. I have seen this pruned to keep it to modest proportions in a small garden and for real excitement you might train a clematis viticella into it. The contrast of the purple flowers with the fine silvery grey foliage of the willow will be a delight.