Plants for the Garden: Climbers and Wall Shrubs
For the keen gardener the walls of a house are a bonus, an added dimension to be exploited by a wealth of plants that could be grown nowhere else in the garden. There arethat, if carefully selected, can provide colour throughout most of the year that, but for those walls, would be missing from the garden altogether.
But there is another bonus that the keen gardener appreciates; brick and stone facing the sun Collect the sun’s warmth, and return it to the atmosphere during the cool of the night, and any inhabited dwelling house gives off an appreciable amount of heat: these two factors together combine to enable the gardener to grow against the walls of a house plants that would be too tender to survive in the open garden; the warmth reflected from the brickwork helps to ripen wood, and the extra warmth in winter can make all the difference between the death by frost of a tender plant and its survival. Thus plants such as the pomegranate Punka granatum and the New Zealand cherry trees Hoheria species and the Australian bottle-brushes Callistemon species will thrive against the south or west wall of a house while they would not stand a chance exposed to the elements in the open garden : these could only otherwise be grown in the greenhouse. For this reason it is worth reserving the south wall and specially sheltered corners for particularly tender and beautiful plants.
Wall shrubs and climbing plants need the same basic treatment as shrubs planted in the open garden: the ground should be well-prepared before planting, and the planting hole should be taken out to an adequate depth and an adequate width. Unless the plant will thrive in a poorremove all builder’s rubble and replace it with good garden soil. When planting a climber or wall shrub make sure that the stem is at least eighteen inches from the wall. The eaves cast a rain shadow, and little rain will fall on the soil six inches to a foot away from the brickwork. Furthermore, the stem that may be planted as a slender twig no more than an eighth of an inch in diameter may in time grow into a trunk two feet thick
Most of the shrubs grown against walls can be allowed to assume whatever shape comes naturally to them: but some need to be kept fairly flat against the wall. Stretch strong wires between masonry nails and tie the plant back to these wires. Put the wires in position before the shrub reaches the stage at which it needs tying to the wires.
Plants climb by one or other of two means: either they cling to any wall or other flat surface by means of aerial roots with sucker-pads, or else they twine themselves or their tendrils round supports such as twigs or trellises. Ivy is a typical self-supporting climber, using aerial roots: wisteria a typical stem-twiner, and clematis a typical tendril climber.
Many different types of support that can be used for twining plants. A trellis of thin wooden strips painted green or stained with a wood preservative is one possibility: another is a plastic-coated wire mesh; chicken wire may also be used: for some plants it is sufficient to stretch wires between masonry nails, the wires spaced 8-12 inches apart. The important thing is that the support is not placed flat against the wall.
Against a pebble-dash finish or white painted wall, fix a trellis or other support to a large wooden frame and then attach the frame to the wall by means of large hinges at the bottom securing the top with simple bolls or latches: all that need then be done when the time comes for repainting is to unlatch the frame and move it away from the wall on its hinges, plant and all. Since the hinges are likely to be exercised only once every four years or so it is important to keep them well covered in a thick layer of grease to prevent them from rusting solid.