Designing a planting space requires considering several elements, such as mass, form, line, texture, and color. These elements are used to transform the space and create a unique experience. Every design is based on common composition tools. When creating a planting design, there are three vertical spatial divisions to consider.
The lowest layer is the soil layer, which consists of low plants such as grass that grow up to 6 inches tall. This layer serves as the base of the composition. The foreground layers are plants that measure between 6 and 2 feet tall. These form the border of plant beds and act as a transition to larger plants.
The middle layer consists of 2- to 5-foot plants that occupy most of the space in the composition and provide spatial definition, join the lower layer with buildings or tall plants, and create color and texture throughout the garden. The highest layer is made up of large trees and shrubs that are often used as screens or awnings to provide shade. The height should waver from highest to lowest and back to highest along the horizon. Avoid large spaces in vertical heights unless the intention of the design is to have drastic differences in the layers.
Mass describes the space or area that an object occupies. Your home, as well as the structures and plantings of a landscape, have mass, as do individual plants. Empty spaces also “occupy a different area”, and empty space is more important to landscape design than occupied space. Color is an important design element but should not be given too much attention.
Line, shape and mass are the bones of a garden; if these structural elements are neglected, a poor design will result. Once the structure is established, color can be used to add interest and evoke emotions. Warm colors (red, orange and yellow) give a sense of warmth and emotion while cool colors (green and blue) soothe and make objects appear smaller and more distant. Purple looks good next to a warm color and looks warm next to a cold color while white is used to contrast and separate conflicting colors.
Dark colors seem to pull away from the viewer while bright colors stand out. Design principles guide the integration and composition of various design elements into a cohesive whole. These principles include scale or proportion, balance, rhythm, emphasis, simplicity, and sequence or transition. The distribution of mass (visual weight) in a landscape creates balance which can be symmetrical or asymmetrical. In an asymmetrically balanced design, the sizes and numbers of the plants are only relatively similar on both sides. Rhythm helps us achieve unity in a landscape by providing predictable repetition of materials and elements such as mass, form, line, texture and color. Too much of one element can make a garden seem boring or uninteresting while too many different elements can create clutter and confusion. Transition is the change through a space or from one space to another.
When two areas have a similar scale, it's best to make changes gradually to maintain rhythm and harmony by changing only one element at a time.