Houseplants help to brighten our homes and they should be regarded as you would any other piece of décor- all of the rules of design still apply. A plant added to any room should brighten and enhance the setting, not take away from it. A golden striped yucca for example, should be placed where the coloring will complement the room, not clash with it.
A houseplant can make an excellent focal point and really improve the way a room feels. If you have a houseplant with deep purple or burgundy foliage you might want to avoid putting it in a very softly colored room that is mostly filled with pastels unless you're looking for a dramatic pop of color. Similarly, an African violet with very pale flowers might look out of place in a room with a very bold color scheme. One should give thought to what colors one is using, and where and how they are being used.
Houseplants improve air quality, and this is a perfectly valid reason to keep some. A healthy houseplant can make a home feel more fresh and inviting. They last much longer than cutflowers, they can be very rewarding and satisfying to look after, and they provide beauty - something which most people need in the winter. Houseplants are typically inexpensive and there is at least one houseplant that can suit every room in your house.
Shape
The first thing to consider when selecting a houseplant is shape. Non-flowering houseplants far outnumber those that bloom, and they come in an unlimited variety of shapes and sizes and colors. What kind of mood do you wish to create?
Some plants, such as cactus and palms, provide strong, vertical lines. Some plants are fine and misty and have a lacy, ethereal quality. Before purchasing, think about the kind of room the plant will be living in. A large aloe or a dragon tree might be just the focal point you need. On the other hand, a bird of paradise or a banana with very large leaves might look ridiculous. The room the plant will be placed in makes a difference.
Texture
Just as in your garden, you need to think about texture. The large, bold leaves of an Alocasia might be just the thing for a room with an African flair. Hard lines and edges might be softened with some fluffy ferns. Stark, austere corners might need something with crinkly leaves. Hanging baskets of succulents could give a room a certain whimsical feel, or maybe you need a fig or a rubber tree with glossy, polished leaves for a smart, crisp look. Repetition (just like in your garden) can add a note of confidence to a room. Regular, repeated patterns create a sense of calm and reassurance.
The three P's
There are three P’s of houseplants design- plant, pot, and position. These three things should always be in harmony with each other. Strong shapes work best with pots that are simple, and the greater the number of repeated elements, the stronger the impact. Using the same plant in multiple places in a room is a good technique, or use the same plant in varying sizes. Succulents often look good when mass displayed, and snake plants and ferns can also look good when used generously. Group arrangements can also look good and they do not all need to be one and the same. They can be used to section or screen off a room, or create boundaries. Climbers and vines can be good choices for growing indoors and can make a tight corner feel less sharp or a high ceiling feel a little less tall. Many of them grow quite quickly.
Plant health considerations
Houseplants need a certain amount of light, and not every room in your home will suit every single kind. Bathrooms are ideal for houseplants if you have a window and/or a skylight. In general, the bathroom is the warmest and most humid room in the house and this suits a wide variety of tropical plants including orchids, ferns, and bromeliads. Kitchens can also be satisfactory places to keep a collection of houseplants.
Low light conditions often frustrate houseplants enthusiasts and stairwells and hallways are often the worst culprits. Apartments, condos, and basement suites are also often lacking in light. There are a few plants that can handle low light situations but not very many. A dim corner is not an impossible place to put a plant, but it will definitely be the most challenging. Sansevieria prefer ample natural light, but they'll tolerate low levels of artifical light.
Sunrooms and conservatories are ideal places to keep houseplants but not all of us are so lucky.
It is also important that we avoid placing houseplants in places such as doorways and near windows that are frequently open since a cold draft can often be their undoing.