How you choose to design your house plant collection depends on your personal style, imagination, and the space you have available. With so many variables, the possibilities are almost endless, but for your displays to be successful, follow these key principles.
1 CARE COMES BEFORE STYLE
A healthy plant is a beautiful plant. When designing for a particular space, always choose plants that you know will thrive in the light, temperature, and humidity conditions provided by that space. There is no point taking the time to arrange the perfect display only to watch the plants within it begin to wilt and die because they are unhappy in their location.
2 THINK NATURAL
Be inspired by nature. Consider where and how a plant would grow in the wild, and try to emulate that in your display. So, if a plant thrives in on a damp, semi-shaded forest floor, provide it with a position that offers a similar environment. If it trails from high branches, place it in a hanging container. If it grows aerial roots without compost, build that into your display. Whatever its natural circumstances, use them as inspiration.
3 HARMONY AND CONTRASTStrike a balance between harmonious and contrasting design features. Familiarize yourself with the four key elements of design, and harmonize or contrast them as needed to achieve the effect you want. Harmony can create a balanced, unified appearance, while contrast will add interest and dynamism to a display.
Source : ROYAL HORTICULTURAL SOCIETY HOUSEPLANT BOOK