Sunday, September 9

Taking the mystery out of shade

Shade gardening offers rich textures, forms and colors

Web Extra: More plants for shady conditions

The Daily Journal/Kim Carpenter The filtered shade found under a canopy of high limbs provides a comfortable home for hosta, ferns and other shade-loving plants in Marcy Stewart-Pyziak’s Wilton Center garden.

There can be something intimidating about garden shade. So much so that many gardeners won’t even try to grow plants in anything but direct sun. But, like every other aspect of gardening, the key is understanding the environment and then selecting the right plants for the job. True, you may not have the selection you have with sun-loving plants, but shade gardening offers rich textures, colors and forms that make it well worth the effort to do it right.

Shade isn’t just the absence of light. There are several different types of shade and plants that grow better in some than in others.

• Light shade means only two to four hours of shade in a given area between 10 a.m. and 6 p.m. This usually occurs where the sun’s rays are blocked for a time by an object such as a fence or other structure. When the sun moves across the sky, the area is sunny for the rest of the day.
• Filtered shade may seem completely shaded throughout the day. But sunshine is constantly filtering through tree branches, pergolas — whatever is casting the shade. Enough of this dappled light gets through that plants are really only shaded two to four hours. Under trees with sparse canopies like the honey locust, there’s only about two hours of actual shade a day; heavier leaves or a denser canopy will cast closer to four hours of shade.
• Part shade means an area is in shade four to five hours. These conditions are often found along a long row of tall trees or large structures — especially east to west. They block the sun longer before it moves enough to get around them.
• Full shade lasts the entire day. You usually find it between the west and east sides of two adjacent buildings, under a north-facing overhang or right up against the base of a tall fence where the sun never shines. However, full shade areas are still lit by skyshine, the defused ambient light in the atmosphere, or by the light reflected from sunny areas or buildings.
• Dense shade is the deepest, darkest, daylong shade. You find dense shade under the thickest, most crowded branches of trees like Norway maple (Acer platanoides) or spruce (Picea spp.) or at the bottom of a canyon of city skyscrapers.

Plants have to be compatible with the shady conditions in your garden, but there are several other situations that also need to be addressed. These include:

Heat shade doesn’t necessarily mean cool temperatures. Shady areas can be warmed by walls, paths and driveways. Take these hidden heat sources into consideration.

Moisture check the soil’s condition. Is it wet or dry? Some shade-loving plants thrive in bogs, but most prefer moist, well-drained soil with no standing water. A few even like their shade high and dry.

Shallow-rooted trees like maples (Acer spp.) quickly draw the moisture and nutrients from the soil around and under them. And they bully most plants out of growing space to boot. Bishop’s cap (Epimedium spp.), cyclamen (Cyclamen hederifolium and C. coum), male mountain fern (Dryopteris oreades) and dalmatian bellflower (Campanula portenschlagiana) grow well under greedy, shallow-rooted trees.

Time of day
The nature of shade varies with the time of day, too. Afternoon shade is usually preferred. It shields plants from the blast of the hottest, brightest afternoon sun. Morning shade can give way just when the sun hits delicate plants like a flame-thrower. Choose plants carefully in that situation. Sedums (Sedum spp.), catmint (Nepeta x faassenii), salvia (Salvia spp.) and tickseed (Coreopsis spp.) can take this afternoon furnace. Also pay attention to when the afternoon shade starts. If it doesn’t get shady until after 2 p.m., tender plants like ferns can fry.

To get insight into the dynamics of your garden’s light and shade, keep a shade journal. Check your site throughout an entire growing season if you possibly can. Pay attention to when deciduous trees drop their leaves. The plants that were in summer shade could be left roasting in the sun later in the year. In the same way, watch what kind of shade develops when the trees leaf out in the spring. Part shade might become much deeper in June.

Count the hours
Time the shade your garden gets and whether it’s morning, afternoon or lasts all day.

Go to the source: Determine whether garden shade comes from open lacy trees, denser canopies, buildings or other hardscape structures.

Track the weather: Get an accurate profile of your shade microclimate with a rain gauge and thermometer. You may have conditions that are surprisingly different from those is the sunny, open parts of your yard.

If you have filtered or light shade, hallelujah! These are the best conditions to grow shade plants in, and there is a large variety available. Some sun-loving plants such as daylilies (Hemerocallis spp.), coral bells (Heuchera spp.), columbine (Aquilegia canadensis) and goat’s beard (Aruncus dioicus) also do well in light and filtered shade. There are fewer plants to grow in part shade, but lily-of-the-valley (Convallaria majalis), lady fern (Athyrium japonicum) and hosta are proven winners.

For full shade, try periwinkle (Vinca minor), pig squeak (Bergenia ‘Perfect’), dead nettle (Lamium maculatum) and moneywort (Lysimachia nummularia).

Dense shade supports foamflower (Tiarella cordifolia), bugbane (Actaea matsumurae ‘White Pearl’), Solomon’s seal (Polygonatum multiflorum), lungwort (Pulmonaria spp.) and Virginia bluebells (Mertensia virginica).

Once you have established the shade conditions of your garden and selected the kinds of plants that will do well there, till in four inches of organic compost to loosen and slightly acidify the soil. Space plants about eight inches further apart than recommended to improve air circulation. Have some stakes ready to support plants that will stretch a bit to reach for the light. Also, don’t forget to mix different foliage textures and colors and spring, summer and fall blooming plants, plus a few shade annuals, so you’ll have color throughout the seasons.

Active in the horticultural industry since 1994, Glen O. Seibert is a former editor for Garden Gate magazine and now works as a writer, landscape designer and self-professed “gardening media mogul.”