Many gardening enthusiasts love spending time in their garden on beautiful, sunny summer afternoons. But what if your garden is in a sunny spot, the temperature is 95 degrees, and the heat index is over 100? What fun is that?
But what if that same afternoon your garden was in a location where it was 20 degrees cooler and you didn't need to apply sunscreen? Shade gardens offer the opportunity to grow plants that wouldn't thrive in full sun and also make gardening more enjoyable on hotter days.
A changing climate is resulting in an increase in extremely hot days in the Columbus metropolitan area, increasing the need for shade in urban environments as well as yards.
Shade definition
Because shade intensity varies, it is important to understand the level of shade in a particular location if you expect the plants in your shade garden to thrive. The following definitions can help gardeners select plants that are appropriate for a location based on the amount of sun or shade a particular spot will receive.
A location in full sun is one that gets at least 6 hours of direct sunlight per day. This doesn't have to be continuous; it could be 4 hours of sun in the morning, shade during the midday, and 3-4 hours of sun in the afternoon. A location in full sun needs to be one that gets plenty of direct sunlight.
In partial sun locations, they get four to six hours of sun per day.
Partially shaded locations receive 2-4 hours of sunlight per day. Partially shaded locations often have obstructed or patchy sunlight, such as under open-canopy trees such as black locust or birch, creating a constantly changing pattern of sun and shade.
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Moderate shade locations receive less than two hours of sunlight per day and are often primarily exposed to reflected light, such as the forest floor of a hardwood forest.
Deep shaded areas, such as the base of a north-facing wall or under a dense evergreen tree, do not receive direct sunlight. All plants need some light to grow and thrive, so few plants will thrive in the shadiest of places.
Shady gardening
In many urban and suburban neighborhoods, where sunlight is limited by the proximity of other homes or an abundance of trees, the best way for gardeners to cope is to embrace the shade and choose plants that thrive in it.
Shade-tolerant plants usually have thin leaves with a large surface area. These plants are structurally adapted to photosynthesize efficiently in low light conditions. Light sensitivity reduces the plant's ability to withstand prolonged periods of direct sunlight.
These plants can usually tolerate some early morning sun, but exposure to midday sun will cause the leaves to turn white with burnt spots and scorched leaf edges.
Keep in mind that over time, the amount and location of shade in a residential area can change dramatically as existing trees grow and new trees are added to the landscape.
When I moved to my Columbus home 13 years ago, the only shade on my large lot was under a large maple tree. Over the years, I've planted dozens of trees, which have created some shady areas where sun-loving plants once lived, and now shade-tolerant plants are thriving.
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Perennials suitable for shade
Perennials are great for creating an attractive shade garden with plants that bloom every year. Choose a variety of species that bloom at different times of the year so you can enjoy color all year round.
Perennials that do well in partial to deep shade include: bloody heart (Lamprocapnos spectabilis), black snakeroot (Actaea racemose), red baneberry (Actaea rubra), lady's mantle (Alchemilla mollis), astilbe (Astilbe spp.), Japanese Paignton (Athyrium niponicum var. Pictum), heartleaf brunnera (Brunnera macrophylla), hosta spp., creeping phlox (Phlox stolonifera), Jacob's ladder (Polemonium caeruleum), and more.
Annuals add color to shady areas
Planting annuals in a shady garden is a great way to add color. Annuals that can thrive in shady areas include wax begonias (Begonia x semperflorens cultorum), impatiens (Impatiens walleriana), lobelia (Lobelia erinus), coleus (Solenostemon scutellarioides), polka dot plant (Hypoestes phyllostachya), and pansies (Viola x wittrockiana).
Shrubs provide height and structure
Most perennials and annuals adapted to shady locations tend to grow less than 18 inches in height, so adding a few woody ornamental shrubs to a shady garden is a great way to give height and structure to the garden.
Woody shrubs grow best in partial shade with two to four hours of sun per day. Shrubs that will thrive in shady locations include Fothergilla (Fothergilla spp.), Oakleaf Hydrangea (Hydrangea quercifolia), Smooth Hydrangea (Hydrangea arborescens), and Arborvitae (Thuja spp.).
I recently planted two red-branched dogwoods (Cornus spp.) in one of my shady gardens for some visual interest during the winter, and while the colors of the stems (red and yellow) may not be as vibrant as when they are grown in direct sunlight, they seem to be thriving.
Diversify your plantings
Consider other types of plants to plant in your shade garden: Ferns are great for shady areas. Native Ohio ferns you can plant in your shade garden include the acid fern (Athyrium filix-femina), the ostrich fern (Matteuccia struthiopteris), which does well in moist, shady areas, and the cinnamon fern (Osmundastrum cinnamomeum), which has tall, arching leaves.
Some Ohio native wildflowers thrive in shady locations, so consider adding plants such as wild columbine (Aquilegia canadensis), wild geranium (Geranium maculatum) and crested iris (Iris cristata).
And on hot days you'll want a cool, shady place to sit and read a book, so be sure to include walking paths, stepping stones, garden benches and chairs in your favourite new garden space.
Mike Hogan is an extension educator and associate professor of agriculture and natural resources at Ohio State University Extension.
Email: hogan.1@osu.edu
