When you are incorporating house plants into the decorative scheme of a room, the same considerations of taste apply as in flower arranging. Is the style of the room formal or informal, rustic or sophisticated, cosy or austere? The choice and arrangement of house plants should follow suit.

There are, of course, other considerations to keep in mind. Plants are more permanent than cut flowers and some grow to be big, so scale is very important. There is less choice about their placement because many need light, a steady temperature and minimal handling.

Some demand a prominent position when in flower, but if their foliage is uninteresting they may need to be moved into obscurity until the next blooming season. Concealed pots of water containing cut flowers can be used to replace the splash of colour.

As with flowers, one massed array is often more effective than pots here and there, provided there is space. But leaves are a permanent feature, so it is important to group together interestingly contrasted foliage - slender and round, fleshy and lacy, upright and trailing, glossy and velvety. Shape may be a more important consideration than colour.

Unless some plants in a group are naturally taller than others, pots at the back can be raised up (empty food cans, well concealed, are useful for this purpose). If the arrangement is below eye-level, the view from above will be most important, but if it will be seen most often from low armchairs, check how it looks from this angle
too. Remember that small plants with delicate blooms will be wasted unless they are near eye-level.

A mass of one kind of flowering plant can provide a dramatic colour accent in a room. A variety of plants and colours will be most successful against a very plain background. In a room with patterned wallpaper or fabrics, it may be best to stick to white flowers or foliage plants - and essential if the group is not near the window. The massing of plants can be accomplished by putting several pots together inside a larger container (like an old preserving pan or Victorian washbasin) or in a trough, or by grouping them.

A shelf above a radiator would be suitable for a group of plants that like dry warmth; a cool, empty grate for Ferns; a tiered table or dumbwaiter for a mixture of upright and trailing plants; even a tea trolley or saucepan rack can be adapted. A jardiniere (of bamboo or decorative white ironwork, for instance) is a purpose-made solution to the problem.

A whole bay window might be filled with plants, particularly if the view beyond is dull. A mantlepiece could be topped with a made-to-measure tray, provided the plants will not be overheated by a fire below. It may be worth fitting wooden steps into a corner or an alcove, so that pot plants can descend, terrace-style, down to floor level.

If a room is too small or crowded for a massed group, there may be a corner where one tall plant can stand on its own; or a striking climber can be encouraged to travel along the top of a bookcase or a beam or decorate a picture rail. A number of such plants are happy in corners with relatively little light. These deserve handsome urns, tubs or containers that can be part of the furniture of the room.

Alternatively, choose a plant that will stay small, put it in a really interesting container, and give it pride of place on a desk or table where its detail can be seen. If a small plant is to occupy an important spot, it needs particularly attractive leaves or flowers or growing habits that are interesting to watch - like Saxifraga sarmentosa (Mother of Thousands) and its babies or Tolmiea menziessii (Pig-a-back Plant), which produces little leaves on top of the old ones. Two small plants, each in a square container, could serve as bookends. Another solution, when space is short, is to hang a group of wall pots containing plants that trail or to fill the shelves of a tall bookcase with plants or to use a long trough in front of a blocked-in fireplace.

Some rooms are necessarily bare of furniture - narrow entrance halls, for instance, and bathrooms. Suitable plants can 'clothe' these places, and make them seem less empty. If the lines of such a room are straight, the natural curving shape of most plants can lessen the stark effect.

On a dinner table, use low plants in conjunction with candles instead of cut flowers. For example, pink Africa Violets with tall candles to match th flowers make a charming combinatio (but use kitchen foil at the bottom t ensure that the candles will not bur low and harm the plants). Or th plants might be grouped around a sma white china figurine.

Miniature dish gardens are suitable fc coffee tables, where their detail can b enjoyed at close quarters, particular! if there is a lamp nearby to light ther at night. Such an arrangement will b seen from all sides, so it needs to b attractive all round, with the taller plants in the middle.