Gardening: A-Z of really small gardens: Container Plants - A potted guide to variety

Ring the changes with clever use of containers. This week's extract from Jill Billington's 'Really Small Gardens' explains how

Containers are invaluable in areas where there can never be soil- filled planting beds - they enable you to grow almost anything that can cope with restricted roots. And many small plots are primarily foliage gardens, relying on flowering plants in pots and troughs for spring and summer colour. Containers can help you ring the changes of the seasons - and the years.

Small containers look much better if grouped, as the picture, right, shows. The formal arrangement comprises clipped box in terracotta pots, circling a container crammed with white-flowered petunias, verbenas, marguerites and silver-leafed Helichrysum petiolare.

Pots with high impact may stand alone as features in their own right. Huge Mediterranean terracotta "Ali Baba" pots or oil jars look best without any plants at all. Simulated lead tanks are large and stylish, ideal for simple feature planting like oleander in warm climates or a Japanese acer or massed white lilies for summer in temperate climes. Stone urns are dignified, so the plants contained within them need to be of similar status. Square Versailles tubs are ideal for single specimen plants like summer- flowering standard marguerites, clipped cones of bay, formally clipped hollies or domes of box. Large and narrow rectangular troughs can be used to grow bamboos, which are normally rapacious rooters, yet great performers when contained. To provide privacy in the small yard, you could lay several of these end to end for effective screening. Wooden troughs give you a real chance to mass summer annuals, mixing pelargoniums, daisy flowers, blue lobelias, silver-leaved Senecio cineraria and verbenas, or rusty orange, mahogany- red and golden tagetes. Fulsome planting such as this will compensate for any restraint in the main garden.

With window boxes, include some plants, like the upright Iris stylosa or Sisyrinchium striatum, which edge your view from indoors as well as those which trail down to be viewed from outside and below, like ivy-leaved pelargoniums, Vinca minor, Helichrysum petiolare and trailing fuchsias.

You can achieve tiered planting effects if some pots are raised on plinths - even above head height. This increases the number of plants you can use, as well as introducing those which like to trail and tumble down to lower levels, such as attractive ivies with a small clematis, slow- growing honeysuckle (Lonicera syringantha) with trailing nasturtiums or lobelias with verbena. It is also effective to have one tall plant in a large container "grounded" by lower-growing ones in smaller pots at its foot, for example Phormium 'Bronze Baby' surrounded by mahogany-coloured Tagetes 'Paprika'. If you plant up some bulbs and follow them with seasonal plants during the year, the looks of your containers will change constantly.

For summer colour, the range is huge and tempting and a small courtyard bursting with flower colour is many people's summer dream. Marguerites, petunias, salvias, verbena, marigolds, begonias, French mallow, lobelia, osteospermums, cosmos and mesembryanthemums plus nicotianas large and small, offer all hues and shapes. It helps to colour-theme the planting in some way so that your small space does not look too hectic. You might condense the colour by planting, for example, mounds of heliotrope with trailing violet-flowered verbena or, in a quieter scheme, planting tall white Nicotiana sylvestris with trailing white Campanula isophylla and a small- leaved green ivy.

For brilliant summer effects, put in flame-orange Dimorphotheca sinuata with other vivid South African plants such as gazanias and nemesias. For shade, there is nothing to beat busy lizzies (Impatiens) in white, vivid pinks or red. Arctotis, with its silvery foliage and rich bronze or orange flowers, is a particular favourite. For best value, choose plants that provide colour into autumn, like petunias, pelargoniums and lobelias.

Permanent planting - such as small rhododendrons - can be a means of growing impressive plants which do not like your soil. So small azaleas, dwarf rhododendrons and skimmias become an option even in areas of alkalinity and camellias, grown away from the morning sunlight have great gravitas. Or you may fill pots with evergreen topiary shapes and dot them around the site. Euphor-bias like E characias and tall grasses like Miscanthus sinensis look distinguished in large pots, as do acers and dwarf shrubs like the flowery potentillas.

The many uses of versatile containers serve to demonstrate the wide range of opportunities available to the small-space gardener. Size will, inevitably, control much of your selection, but once you understand the factors that limit choice, you will be free to explore the small garden's potential.