The scope of indoor plants is anything from a few pots brightening up a dull corner, to a luxuriant garden room bringing freshness into the house.  Indoor plants not only freshen up the air in the house, they also bring vibrancy and color, which raises the spirits of anyone in the vicinity.

The House Plant Expert: The World's Best-Selling Book on House Plants

Size and Proportion.

A mass grouping, or large plants in the house need a large open area or a big room, so as not to overwhelm the space.  Examples of this would be tall climbers or baskets of spreading or trailing plants, or even a room divider constructed so that plants can climb through it. 

 If, on the other hand you have a small area or corner that just needs brightening up, a single plant in a decorative pot with an ornament or two will do the job.

 Something else to keep in mind when thinking about arranging indoor plants is that you can create different effects using the same plants, so experiment with the placement until you get the position and arrangement that you like best.

How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office

Display.

Different levels can be used to display your indoor plants to effect.  Use a table top for small to medium groupings; shelves or ledges at or below eye level for individual display plants; and a position above eye level for trailing or cascading plants.

 It is important when placing indoor plants to consider the light, furnishing style and color and also the background color.  It is no use placing a something with dark leaves in front of a dark wall, as the effect will be lost.  On the other hand, you could have light foliage, such as a fern, in front of the same wall and it would show to advantage.  Most plants look good in front of light colored walls or in front of a window.  An ideal spot, because of the ambient humidity, is in front of a kitchen window if you have the space, or in a bathroom if it is light enough.

 Another trick to highlight plants indoors is to have a spotlight shining on them.  This can be used just at night, when you want a highlight, or can be used more often to give more light if it is in a very dark area. 

There are several ways to group plants for display indoors.  One way is to have each different type in a separate decorative pot and the display will then consist of the whole collection of pots and plants, all working in together.  Another way is to have one plant in each pot, but then group all the pots in a large decorative container so that the individual pots aren’t seen.  You could also plant up a large container with a variety of contrasting color, texture, pattern and shape.