Natural Color for Shady Landscapes

One of the most daunting challenges facing the average gardener is planting in full shade. Not the partially sunny, light-dappled kind of shade that feels so lovely in midsummer, but the deep Amazonian shade so dark that moss will grow on your garden trowel if you don’t keep moving. Not surprisingly, many folks facing full shade simply give up and resign themselves to a dull landscape of invasive ivy and much over-utilized liriope, little realizing that there are ways to foster splashes of vibrant color even in their horticultural twilight zone.

One possible approach is to treat a fully shaded yard more like a natural woodland area, selecting a variety of native plants which are generally well-suited to low light conditions.

You might start by seeing whether your landscape can use some small trees and shrubs. For example, while many yards are full of tall, mature trees, such as oaks, hickory, and poplars, there is usually little else growing between the sky-high canopy and the ground below. Filling that space, the “understory,” is the first best place to begin adding color.

Some suggested specimens include Shadbush, which provides white flowers in spring and brilliant foliage in autumn, and Redbud, which also features pinkish-purple spring flowers and red leaves in fall.

Fringe tree is one of the true delights of our local woodlands with extremely fragrant, pendulous clusters of bright white flowers, as is Sweetbay Magnolia, with large aromatic white flowers and brilliant red berries.

Virginia Sweetspire produces long, fluffy racemes of fragrant white flowers in summer, followed by wine-red foliage through autumn and early winter.

And finally, round out these aromatic offerings with Sweet Pepperbush (Summersweet), with its tempting midsummer display of apple-pie scented, pinkish-white flower spikes, usually heavily-visited by butterflies, and an encore of yellow foliage in fall.

Beneath the understory, you will want to introduce a full array of woodland wildflowers, which can expand or reflect the key elements of this region’s natural habitat. Be sure to keep succession bloom in mind as you select your plants. For example, a great many woodland plants will put on a fine show in early through mid-spring but these “ephemerals” will soon fade, leaving you with foliage and fond memories.

That is not to say that you should not include spring ephemerals, which are often among the most spectacular plants around, such as Virginia Bluebells, which explode in April yet sadly fade in May. But think in terms of plants which will flower at different periods throughout the year, and which can do double or triple duty with autumnal color and/or colorful fruits and berries.

Some native selections, such as Great Blue Lobelia and Columbine, also readily attract butterflies and hummingbirds, which is yet another way to introduce color into your garden – and into your life!

Great Blue Lobelia should also be greatly valued for its brilliant bluish-purple tubular flowers. These appear on one-to-three foot long spikes which bloom from August through October. The species is cousin to the showier Cardinal Flower, but performs far better in partial to full shade. Moreover, the spikes also make for excellent cut flowers, if you can bear the thought of removing them from your garden.

Our native Columbine is favored for its nodding, bell-shaped flowers with tubular red petals or “spurs” and yellow center or “lips” which appear through April and May. The foliage provides a variety of color as it changes during the year from green to shades of maroon. It also reseeds easily, helping it to fill in spaces like a ground cover. Note that in addition to the native species, there are cultivars available which can offer extended blooming periods and exquisite color combinations, such as creamy white flowers with golden centers.

Dutchman's Breeches is another ephemeral native with small, fanciful white and yellow flowers on arching stems or “scapes” and delicate, fine-cut light green foliage. Unfortunately, the flowers only appear from early to mid spring. On the other hand, a close relative, Wild Bleeding Heart, provides the same light touch with wispy mounds of seemingly etched foliage, but with delicate rosy-pink, sometimes purplish, heart-shaped flowers that last from mid-spring through fall.

Alumroot (Heuchera) provides year-round interest with semi-evergreen ruffled leaves which often appear silvery-white with a network of green veins. Some plants also show splotches of reddish-purple, which will spread across the leaf surface and turn progressively darker as summer creeps towards cooler weather. Slender stems or panicles with small bell-shaped flowers appear from April through June. Alumroot makes an excellent ground cover or edging plant if established in thick masses. And look for some of the popular cultivars, like ‘Coral Bells’ which features much darker green leaves, bright, almost reflective silver highlights, and deep red veins.

Foam Flower is another excellent ground cover which spreads readily through underground rhizomes and seeds. Like Alumroot, it is also semi-evergreen, with green foliage that turns maroon as the weather gets nippy. White flower spikes appear from early spring through midsummer, although hybrid varieties, such as ‘Spring Symphony,’ develop spikes of flowers in a pastel pink, almost 18 inches tall, which will last from summer through fall.

For a bit more height in your understory, consider planting several masses of the native aster, with several species readily available which will produce dense clusters of snowflake-like flowers on two-to-three foot upright stems starting in late summer and lasting until close to November. White Wood Aster produces a cloud of butterfly-friendly flowers with very small white petals and a yellow centers which will gradually turn reddish-purple.

Blue Wood Aster has even showier flowers ranging from pale blue to violet, and have inner pale yellow disk florets which turn reddish-purple as the flower matures over several months. Both White and Blue Wood Asters naturalize (spread) rapidly in the garden using both seeds and rhizomes.

And because no woodland is complete without ferns, consider adding ferns to fill in empty spaces and provide some interesting texture or structure against which your other wildflowers can shine. Christmas Fern will provide evergreen, leathery fronds, while New York Fern offers both a more delicate array of pale green fronds, and it will also spread rapidly, closing ranks with your other ground covers.

Copyright 2009, Joseph M. Keyser

Landscaping to Keep Cool - and Save Money!

Ah summer! The evening air is filled with the seductive smell of cookouts and steamed crab -- and the annoying hum of air conditioners. As the mercury keeps inching up into the nineties, the rising cost of keeping cool becomes more of an issue for many homeowners. Fortunately, there are landscaping solutions that can help save on energy costs without forcing you to break a sweat.

By properly positioning trees around our homes and reducing the amount of sunlight striking rooftops, walls, and windows, we can lower cooling costs by up to 25 percent. In fact, this type of natural cooling is much akin to using hats and sunscreen to protect delicate skin from harmful solar radiation.

Typically, the first step in an energy-efficient landscape is to plant a tree or trees on the south or southwest side of your home, where they can block the majority of sunlight, especially that striking your home in the mid- to late-afternoon. A couple of large trees, such as maples, oaks, and ash, will obviously produce the most shade, although smaller trees, such as dogwoods and serviceberry, can effectively screen the sides of a house.

Larger trees should be planted no closer than 20 feet from the house; smaller trees no closer than 15 feet. Among the fastest growing large shade trees are tulip poplars and sycamores, although both have somewhat weak branches and should never be planted where limbs can actually overhang the roof.

Deciduous trees, those that lose their leaves in winter, are more often planted than evergreens, as it generally desirable to allow the sun to provide passive solar heating in winter, at least for walls and windows. However, native evergreens, such as American holly, eastern red cedar, and eastern white pine, can also be used, depending on your overall landscaping theme.

Of course, if you plan to install photovoltaic cells or solar heat collectors on your roof, taking advantage of all that free solar energy, you will want to avoid shading the future location of your solar array. In this case, plant smaller growing trees that will primarily shade walls and windows.

If your property space cannot accommodate large trees, you can provide shading to walls and windows with small trees and shrubs like redbud, viburnum, deciduous azaleas, and inkberry holly. Be sure to keep shrubs about five feet away from the foundation to prevent problems with mold, mildew, and insect pests.

And while working around the foundation, why not use some evergreen shrubs like Mahonia and inkberry holly to shade your heat pump or air conditioner compressor. You will improve their efficiency, reduce some of the whining-whirring noise, and screen an otherwise unattractive bit of technology from view. Be careful that plants do not block airflow to and from the devices.

Another creative possibility is to use vines to shade wall areas and windows. Vines can either be trained to cover wall spaces, or can be attached to arbors and trellises. For example, Virginia creeper (or woodbine) can climb up the side of a masonry-covered wall without support, providing lush, attractive shade equaled only by its crimson-purple autumn foliage. Climbing hydrangea (Hydrangea anomala ssp. petiolaris) is also able to climb without support – or damage to building surfaces – and is a hardy and brilliant white-flowering specimen introduced from Asia in the 1860's.

Trellis structures can support a wide variety of vines and climbers, from showy roses to native favorites such as coral honeysuckle, crossvine, virgin’s bower, and American bittersweet. You can even take an edible landscaping approach and train pole beans or hyacinth beans to climb up string or wire supports.

It should be noted that shading fully exposed windows is more important than shading walls, most of which are fully insulated. For this reason, arbor structures built along the south side of a house can provide shade like a living awning, but with a great deal more beauty. You can train a host of interesting vines along the arbor, from edible kiwis and grapes, to ornamental hops and American wisteria.

Less involved window shading can be created with ordinary window boxes. Consider using some of the more colorful varieties of sweet potato vine, featuring dark purple, chartreuse, or tricolored leaves. These can be planted in your window box along with other colorful annuals and then trained to grow up and around the window frame. You will block out some of the sun’s heat while providing a dazzling window to the outdoors.

After addressing some of the direct sources of sunlight, think about the energy reflected from patios and walkways. Even the air temperature over grass is about ten degrees cooler than that over asphalt or other artificial surfaces. Simply shading these “hardscaped” areas can help appreciably, or you might want to reduce or replace concrete paths with natural, living materials, such as thyme lawns or mulched paths with herbal borders [see “Fragrant Pathway”]. Moreover, you can improve on the air conditioning benefit of lawns by replacing turf with clumps of native and ornamental grasses, perennial beds, and colorful groundcovers.

Keep in mind that landscaping to reduce energy costs can extend beyond merely shading rooftop and windows. According to national energy conservation expert Karen Anderson at the Alliance to Save Energy, “If it looks cool, it is cool.” Ms. Anderson is referring to the impression we have of a typical forest scene: green, serene, and lush with tall trees, ferns, and the leafy masses of smaller trees and shrubs. It always seems quite a bit cooler in such inviting environments because wooded areas really are cooler.

Trees and vegetation actually provide some chilling benefits through evaporative cooling, the transpiration of water through plant leaves. Research by the Lawrence Berkeley National Laboratory found that midday air temperatures were up to six degrees cooler in tree-shaded areas compared to treeless neighborhoods.

If you want to lower summer temperatures all around your home, try creating your own personal forest by grouping trees together in small groves and expanding green areas with ground covers and shrubs.

The more tree cover you establish, especially if it can help shade hot streets, sidewalks, and driveways, the cooler your immediate landscape will be. Naturally, if you work through a community association to get trees planted along streets and common areas, you can beautify your neighborhood, enhance overall property values, while keeping all of your homes more comfortable and energy efficient. Now that’s a cool idea!

Copyright 2009, Joseph M. Keyser