Author: Steve Parrott (Published in Landscape Contractor National)
Plant Illumination
Plants and flowers differ in how they reflect, absorb and transmit light. This is important because they appear differently when lit from above, below or behind. Thick waxy leaves look black if they are lit from behind or below, while thinner, more translucent leaves glow with an ethereal beauty when the light source is behind them. Keeping this in mind, whenever possible we project light in ways that best enhance the viewer’s experience of plants’ inherent beauty.
Path Lights
These fixtures, such as Mushrooms and China Hats reflect light from under their hats to spread a diffuse circular area of lighting on the plant material and hardscaping below. When used along a path, they can be staggered along the edges alternating from one side to the other. They should be spaced far enough apart so that bright regions do not overlap, but not so far that completely dark areas separate them. The path lights can also stray from the path and sit among the garden areas. The selection of these locations is critical and depends entirely on the landscape design.
Bounce Lighting
A variation of down lighting, illumination that bounces off the undersides of gutters, sidings or trees can provide an extremely diffuse and subtle lighting on garden beds. When lighting the side of a house with MR-16 directional light, tilt the fixtures so the beam reflects off the underside of the gutter. The reflected light can illuminate the entire garden bed around the house. For gardens situated underneath trees with fairly low branches, up lights will bounce back to a degree defendant on the reflectivity of the branches and leaves.
Up, Side and Back Lighting
When we illuminate plants from underneath, the side or behind, we see a combination of light reflected off the leaves and transmitted through the leaves (as though the leaves are glowing). With downlighting, we see only reflected light. In lighting plants low to the ground, care must be taken to ensure that hot spots will not over-illuminate plant regions. Careful aiming and the use of diffusion or optical spread lenses can reduce the hot spot and ensure that plants receive an even and non-distracting light. This type of lighting also creates the opportunity to direct shadows from the plants on building surfaces and retaining walls. Plant shadows are often the most impressive defining effect in a landscape lighting design.