American gardeners, who are very good at inventing names that are highly descriptive, often refer to the trees and shrubs used in gardens as foundation planting. This expresses perfectly one of the major roles which these plants perform in providing the permanent framework into which other plants with a shorter life or a greater need for renewal can be fitted. Because they are the foundation of the whole planting scheme, one grasps immediately why they must be considered with the greatest care and why also, as a rule, this must be done at the beginning of every new planting scheme or, if this is quite impossible, a very clear picture of where these foundation plants are to go must be in mind before anything else is put in.
However, though this foundation role is immensely important, it is not the only part that shrubs have to play in the garden. They provide some of the shade and shelter that can be so much appreciated by other plants, they assist in preserving privacy and they can also cut out much of the noise of the
outside world. Theircan be very valuable in binding the soil on steep slopes or in other places subject to erosion, though it must not be overlooked that the of some species can be so numerous, so near to the surface and so hungry that they can make life difficult for close neighbours.
Shrubs can be divided into evergreen and deciduous kinds, the former retainingcover throughout the year, the latter dropping all their each autumn and producing a new lot the following spring. Both types have their value and the proportions in which they are used need to be considered carefully.
Evergreens tend to dominate in winter when their solid shapes stand out conspicuously amid the tracery of bare branches of deciduous trees and shrubs, and at this season they provide much of the shelter, which can be very important for plants growing close to them. However, deciduous shrubs offer the advantages of constantly changing patterns, textures and colours which can be entrancing. It is broadly true to say that a garden with too many evergreens can be heavy and dull and that a garden with too many deciduous trees and shrubs can seem bare and bleak for five or six months each year. The ideal is one in which there is a constantly changing pattern with new combinations of colour and form emerging all the time and never a dull moment from January to December.
Into this scheme of permanent planting, perennial or shrubby climbers fit perfectly.
They too may be evergreen or deciduous, and they too are there all the time, though it is fair to observe that deciduous climbers in general have considerably less to offer in winter than deciduous trees and shrubs since most of them are then reduced to a more or less meaningless tangle of growth and may even, in some cases, need to be cut back almost to ground level. Yet by summer these same plants can have shot up to 15 or 20 ft. and be draping walls, screens, buildings and even trees and shrubs with their leaves and.
If one thinks of garden planting in terms of interior décor (and for very small gardens it is by no means an inappropriate comparison), shrubs may be regarded as major objects of furniture and climbers as wall coverings, curtains and other drapes. Where the comparison breaks down is that a room remains much the same at all seasons, whereas a garden is in a state of constant change which is one reason why making a garden and then living with it can be so very exciting and satisfying.
This raises another point that must be carefully considered. Shrubs may continue to increase in size for many years. If they are planted sufficiently close to give a well-furnished appearance almost from the start, they are certain to be overcrowded after a few years, yet if they are spaced at the outset to accommodate their ultimate proportions, the garden may well appear thin and poorly balanced for a long time.
There are several ways in which these difficulties may be overcome. One is deliberately to overplant at the beginning in such a way that there can be a progressive thinning out of plants over the years without materially upsetting the balance. Another is to use some swift-growing shrubs to give a quick effect with the knowledge that they will be too big, and so will have to be removed, after a few years, and at the same time to plant slower-growing kinds which will be ready to take over when that time arrives. Yet a third way is to plant the trees and shrubs thinly and to fill in during the early years with herbaceous and bedding plants which by their nature must be frequently renewed. All three methods have their merits and drawbacks and which is chosen must depend upon personal preference and circumstances.