Interesting as the attributes of any single plant may be, it is the way plants blend together to create a pleasing whole that is the key to a successful planting project. In order to maximise year-round interest, you need to distribute plants with diverse attractions in different seasons throughout your design.
Many gardeners have a list of favourite plants, but these should take second place behind plants that thrive in your particular garden. Flourishing plants do not require special treatment, and the amount of pest and disease control required will be minimal.
Flower colour and shape will always be a significant factor in the choice of garden plants, but there are other attributes to consider. Foliage effects – variegation, texture, leaf size and shape – are just as important in a well-designed garden, as these are the enduring backdrop throughout the year. Coloured or attractively peeling bark will lighten the mood of any planting, and even coloured or prominent thorns can make the difference between a run-of-the-mill border and one that is out of the ordinary. Ornamental berries, seed heads, cones and pods all have a major part to play in the garden later in the year, and sensory plants – those that rustle in the wind, are pleasant to the touch, or have fragrant flowers or aromatic leaves – are also a vital part of the garden experience.
If you want a colour theme for your bed or border, it is best to group the possible plant choices into ‘hot’ colours, such as bright reds or oranges, and ‘cool’ ones, such as soft pinks, blues or whites. For a harmonious environment, choose closely related colours such as blues, violets and purples; or reds, oranges and yellows, according to your ideas. A more stimulating atmosphere is created with strongly contrasting colours such as orange and blue, yellow and purple, or green and red.
Once you have decided which plants you are going to incorporate into your design, you can then plan how best to position them within the garden. Vary the plant heights as much as possible. In a border, the plants should generally increase in height from the front to the back, whereas in an island bed the plants should gradually get taller towards the middle on all sides, but one or two taller plants among the shorter species can add interest, provided they do not totally obscure the plants behind them. Sometimes tall plants may throw the surrounding area into shade, in which case appropriate shade-loving plants should be used in the shady position. Often a single plant of a completely different shape or style can be included for architectural interest or as a highlight. For example, a yucca in a border comprising mainly herbaceous perennials, or a columnar conifer at intervals among a bed of roses, or a group of white shrub roses in an all-foliage design, may be just the feature to lift a planting to the spectacular.
Low-growing and carpeting plants might be best used as border edging, and other plants will need to be placed in a good spot for sun or dappled shade, for moisture or free drainage. One plant may need to be planted close to another in order to get the best flower, foliage or other effect from both.
Climbers and Wall Shrubs
A pair of climbing plants with similar habits but of different species and with different flowering times, such as Clematis alpina (early flowering) and C. viticella (late flowering), or early dutch and late dutch honeysuckle (Lonicera), may be planted close together to prolong the season of interest in a particular spot in the garden. They should, however, have similar pruning and other care requirements.
Climbing roses make a good natural support for moderately vigorous, scrambling plants such as some hybrid clematis and twining honeysuckle. Rambling roses would be unsuitable for this purpose, as they are pruned after flowering just when many climbers are coming into bloom. Some shrubby wall plants, especially those with a short or early flowering season, such as ceanothus and chaenomeles, can also be combined in this way.