Gene Bush is a nationally known garden writer, photographer, lecturer and nursery owner in Depauw, Ind. Contact Gene at munchkinnursery.com. He is also the author of the blog Shade Solutions.


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What (Exactly) Is Shade?
by Gene E. Bush    


Oakleaf hydrangea, wood poppy, blue wood phlox and Jacob’s ladder make a gorgeous mix. There is no shortage of plants for a shade garden, only a lack of awareness.
(Photo
courtesy of Gene Bush)

Shade in the garden is not a malady, curse, or something less than optimal. It is an opportunity! Knowing what type of shade you are dealing with will help you select plants that will thrive. I have seen the definition of shade split into eight descriptions. Everyone seems to have their own loose interpretation of what shade is. Often those descriptions overlap almost to the point of being meaningless, especially to a gardener newly introduced to gardening in less than full sun. So, exactly what is shade and how do I garden in what some gardeners may think of as less than optimal conditions?

Light comes from the sun and travels in a straight line. If an object gets between the sun and you there is an absence of light—we call that shade. This light, and its absence, can be measured in foot candles. Photographers use meters to measure light when they want to determine an exact exposure for a photo. Some greenhouse growers need exact knowledge of available light for controlling plant growth. Gardeners do not need to be so precise in their knowledge of how much light is available for their plants. After all, gardening is usually more about the art of gardening than the underlying science.


Impatiens Infinity White (photo courtesy of Proven winners)


Hosta ‘Hoosier Harmony’ (Photo courtesy of The Flower Fields)


Trillium with foamflower is one of my favorite combinations using native shade perennials. (Photo courtesy of Gene Bush)


Indian pink (Spigelia marilandica) is our most showy native perennial for shade and enjoys southern or eastern exposures. (Photo courtesy of Gene Bush)


Epimedium grandiflorum ‘Lilafee’ does best with plenty of light such as a southern exposure, followed by eastern locations. (Photo courtesy of Gene Bush)


Variegated Solomon’s seal (Polygonatum odoratum ‘Variegata’) is an easy-care perennial for eastern, southern and northern exposures. (Photo courtesy of Gene Bush)

What makes defining shade so fuzzy is in all the details. For instance, if you live south or north of my location, the intensity of light will be stronger or weaker for your garden than where I dig in the soil. The sun travels across the sky east to west, morning to afternoon, so shade continually moves. Morning sun is weaker than the intensity of afternoon sun, so you can still get eight hours of full sun even if you have morning shade. At some point you will need to stand several times a day where you want the plants to grow and make notes about where the sun and shade is located and how long it remains at that location.

Perhaps shade could, at least initially, be defined by the environments gardeners encounter on their property when physically locating gardens. Perhaps you want to locate a perennial border next to your home, garage or out building. Each side of your home faces a different direction and may offer different exposures, requiring different plants. You may have a backyard with mature deciduous trees. Perhaps there is a row of privacy pines or hemlocks across the back of your yard. Most of us seem to bump into similar situations.

The most difficult location in shade gardening is under the open edge of a deck, or beneath evergreens with limbs close to the soil. Very little light reaches the soil under these conditions and few perennials will thrive. My usual suggestion is large stones that look interesting accompanied by a garden ornament rather than struggling with growing plants under these low-light conditions. This environment would usually be referred to as “deep shade.”

A northern exposure has for centuries been the favored light for artists. While northern light has produced masterpieces for artists, it is not the light of choice for gardeners. Perhaps the site you have chosen is located on the north side of a tall board fence, a row of evergreens, the back of your home or side of a garage. Shade here will generally be open to the sky, but there will be no direct sun. However, with decent soil, it is a good light for perennials such as ferns and hosta.

If you plan to garden on a site that faces west, and receives sun from about midday to sunset, then the location is receiving a full eight hours, or more, of sunlight. As this is also the most intense light of the day it would be considered a “full sun” site. In my shade garden I have sun plants such as shrubs and peonies located on the west side of the garden with shade plants located on the eastern side, or on the shade side of the shrubs.

South is full sun in or on your face from sunrise to sunset. This is the best location for a vegetable garden or full sun border. If there are mature tree canopies overhead, then the light would be on the move providing what would be referred to as “high open shade,” or “dappled light.”

Eastern exposure is the pinnacle of shade gardening. From sunrise until about noon is the softest and gentlest exposure while providing enough light for a perennial to thrive. Woodland plants thrive under eastern exposures when there are trees or other obstacles protecting them from the afternoon and evening sun. If your site is located where you can see the sun rise, you are a fortunate gardener—for, with some careful selecting, full sun plants can also be grown in this exposure, providing an even broader selection of material.

I have the best of all worlds in my garden for I live on the north side of a hill. The sun rises on one side of my garden, and travels across to set on the opposite side so that all light continually moves. Both sides and front of my trees and shrubs receive light, but only for a short period of time.

These simple descriptions are beginnings, for one must eventually factor in such conditions as clay, sandy, rocky, or rich soil; and, in some cases, soil pH. Will the site be considered dry shade? Will it continually be wet shade? Does it have good soil but heavy root competition with mature trees sucking up moisture and nutrients?

Once exposure and environment is known, then the wonders of plant selection begin to match the needs of our individual gardens. Once shade is determined for your site, then research needs to be done on what plants will grow best in that environment. While it all may sound a bit complicated, it is in reality an opportunity to turn loose the creative artist that resides in every gardener.

 

Shady Definitions
Cardinal points are four basic directions on a compass. Facing the sun at noon will give you south, with north behind you, east located to your left and west to right. With this in mind gardeners can know what to expect when locating their shade gardens.

•  Eastern exposure from sunrise to about noon is considered the “perfect” location. Sunrise is the most gentle of light.

•  Northern exposure is light without direct sun, a lack of shadows, and is often referred to as the “artist light.” This would be my second choice for creating a shade garden.

•  Southern exposure will need something, such as trees or shrubs, to screen off direct sun for most of the day. Sun will travel across your garden in this location and can be a good site for mixing some sun and shade plants together.

•  Western exposure is the least desirable location for a shade garden as it will be afternoon sun. The most intense part of light, good screening will be needed along with some extra attention to moisture.

 

 

Posted: 07/20/11   RSS | Print

 

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COMMENTS

TheWriteGardener - 08/15/2011

Although I’ve been writing about gardening for almost eight years now, I rarely talk about light as you have here. You said it best: “I have seen the definition of shade split into eight descriptions. Everyone seems to have their own loose interpretation of what shade is. Often those descriptions overlap almost to the point of being meaningless.”

I think that’s why I rarely write about it.

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