As specimens in paving, lawns, etc. Well shaped, suitable shrubs and trees and most conifers are very useful for this. Trees and conifers look quite nice either singly or in correctly spaced groups. Be careful with shrubs planted this way – they can sometimes look fussy and make a lot of work mowing and trimming round.
In ‘specialist’ beds and borders. Whether you fancy this is largely a personal matter. You might like large areas given over to, say, all conifers of contrasting forms, all heathers similarly contrasted, all grey or yellow foliaged shrubs, all evergreens, all rhododendrons, etc. Conifers and heathers treated this way are quite attractive, but some one-colour borders can be frankly dull. In any case, only those garden owners who have enough space to try this will be able to consider it.
In shrubberies. Strictly speaking, shrubberies are beds and borders containing only plants of permanent woody top-growth, and this can include trees and conifers. The inclusion of any other subjects – bulbs, hardy or half-hardy herbaceous plants, annuals, perennials, etc., technically makes such a planting a mixed border or bed.
When designing a shrubbery, remember the following points: Leave sufficient space between individual permanent plants. If, like Nature, you abhor a vacuum, you can always fill the bare ground up with something temporary.
Try to include subjects which do not all do the same thing at the same time — use flowering shrubs which come out during different months, evergreens, plants which have berries as well as flowers, leaves with good spring or autumn colour, shrubs with variegated foliage, or coloured bark, etc.
Arrange your shrubs so that they contrast and complement each other – different coloured leaves, different foliage or habits, a good balance of evergreens to deciduous shrubs, and so on. As a general rule, shrubberies should be designed with the taller plants towards the back (or middle, in an island shrubbery), the shortest at the front, but providing you do not obscure the ones behind, you can bring a few taller subjects nearer the front to break up the rather regimented effect. There should be a reasonable difference in height between the taller shrubs and the ones in front in every case so you can see the maximum of each individual. Do not plant the more tender sorts where they can be damaged by cold winds — at the front, or, more commonly, the back. Sometimes conifers can ‘brown off’ considerably during periods of frosty wind, so ones for exposed places should be chosen with care. Position conifers so that as much as possible of each one can be seen.
Ornamental trees are used in a shrubbery, apart from other effects of foliage, form, flower or bark, to give additional height. Do not choose ones that will eventually make a very big canopy, and remember that the head of the tree will get bigger in time, so plant shrubs nearby which are suitable for growing under trees.
If you have only a limited space, choose shrubs that do as much as possible — for example, if they only have a short flowering period, don’t include them if the out-of-flower habit is dull or untidy unless they have, say, berries, good autumn foliage, or coloured bark.
Do some research first on the conditions preferred by the shrubs you have in mind. Whereas most favourites will tolerate a range of soil conditions, there are many which will not thrive in a limey soil — rhododendrons, azaleas, pieris, for example. Others, like cornus (dogwood), prefer the ground to be moist but most conifers will not put up with a constantly soggy position. Of course, you can try to alter conditions in the locality of the shrub if you simply must have that particular thing, but in the main it is best to choose varieties suitable for what is already there, and create whole areas elsewhere in the garden to provide special conditions of some kind if you must go against nature.