Think about height levels in terms of how they relate to the adult human body, which affects how they are viewed and experienced. Anything below knee height is viewed from above. Waist-high elements are seen at an angle, and form a screen, partly blocking views of anything immediately behind them. At shoulder and head height, dense or opaque elements (such as closely planted tall shrubs, hedging, or high screens) will completely block a view. Structures above head height, for example a tree canopy, can create a sense of seclusion.
Few built elements can compete with a mature tree for interest and drama. If you don't have mature trees you can create fixed elements using hard landscaping, then increase interest by combining plants of different heights.
Contrasts of Height
A range of height levels gives variety and interest to a garden, whatever its scale. Elements that create instant height include barriers (walls, fences, screens or trellis), overhead structures (pergolas, arbors or canopies) and play equipment, such as a child's swing. Various planting items, including trees, shrubs, bamboos, climbers, hedges and perennials, gain status when paired with low plantings, below.
When installing new elements for height it's important to consider your budget...and patience. Young trees and shrubs are less expensive, but they take time to gain height. Built structures cost more, but they make quick work of vertical space.
Combining trees and shrubs behind trellis screens provides partial screening and privacy from neighbors. A painted frame adds height and structure to an otherwise small space.DK - Garden Design © 2009 Dorling Kindersley Limited
Pergolas and other built structures provide height and solid overhead planes, but they need support and can fill small gardens with posts. Instead, consider suspending temporary canopy screens to create shade and make the garden feel more intimate. Lightweight sail-like screens need to be attached securely, but they can also be taken down when not in use.DK - Garden Design © 2009 Dorling Kindersley Limited
Trellis, glass and other transparent and semi-transparent screens help to separate garden spaces, without reducing the available light. They are useful in smaller plots, where they break up the space and add change of mood while maintaining visual connections to be made. Open latticework may be left open, screened with evergreens or used to support climbing plants.DK - Garden Design © 2009 Dorling Kindersley Limited
This patterned glass panel, an attractive feature in its own right, allows light through but slightly obscures the visual connection to the next area of the garden.