When researching the possible plant selections for shade gardens, you will invariably find yourself in the woodland gardening section of most gardening books. Woodland plants are associated with shade since that is or was their native habitat. Woodlands, unfortunately, bear little resemblance to most people’s gardens. Along with shade, woodlands are rich in earth that is teaming with moisture and life. The north side of a building is not.
Shade gardening in the urban or rural environment usually means dealing with a part of the garden which has limited sunlight because of buildings, fences or large trees nearby. It is the most challenging of all gardens since colour cannot be the primary design feature. Foliage, texture and shape are the primary attractions along with subtle and sporadic flowering.
Shade plants traditionally have large leaves to capture as much sunlight as possible. Variations in leaf shape, size and colour are critical features when selecting an attractive combination of plants. Flowers are often white to reflect light and capture the maximum amount of the sun’s energy. Shade plants also tend to creep along the surface in search of sunlight, and intermingle with other plants. Lady’s Mantle (Alchemilla) will wind its way around Yew (Taxus) forming a lovely assortment of shades and textures. Lupins (Lupinus) look marvelous shooting out of a sea of Sweet Woodruff (Galium). These types of plant associations are essential in shade gardens. It is difficult for one plant to stand out on its own, at least for very long.
There are different types of shade ranging from dappled sunlight offered by the filtered shade from trees or shrubs to dense shade from the shadows cast by buildings or fences. Filtered shade offers the greatest selection of suitable plants including spring flowering bulbs which need the sun in early spring prior to the trees leafing out. Some sun-loving perennials can survive in filtered shade although they will not excel in form, flower or fruit. In many cases, this can be an advantage. Gooseneck Loosestrife (Lysimachia), for example, is an aggressive grower in full sun but will be kept contained in shade. Lilies and roses which are traditionally thought to be sun-lovers, will perform in situations where the base of the plant is shaded but the tops can grow out into the sun.
The most difficult situation occurs when the shade is cast by the dense canopy of a tree with a shallow root system, for example Norway and Silver Maples. The lack of moisture in combination with the lack of sun make it a challenge for anything to survive. After spring flowering bulbs, there is little else available to the gardener. In these situations the gardener should attempt to remove tree roots so that other plants can pick up moisture. Severing major roots will help temporarily but the tree roots will continue to branch and suck up the available moisture. Some reliable perennials to try in this situation are Barrenwort (Epimedium), Dead Nettle (Lamium), Lily-of-the-Valley (Convallaria), Chamomile, Periwinkle (Vinca), English Ivy (Hedera), Euonymous and Sedum. Shrubs which might work include Yew (Taxus), and some varieties of Spirea. Mulching, watering and top-dressing with rich soil will help to get these plants established.
Another difficult situation is dense shade caused by the shadows cast by a fence, building or other object. The variety of suitable plants is greater here since moisture does not have to be limiting. The soil can be amended with organic matter, making a deep, rich mixture, suitable for a wide variety of woodland plants. Foamflower (Tiarella), Hosta, Ribbon Grass (Phalaris), Foxglove, Lady’s Mantle (Alchemilla), Hydrangea, Ferns, Sweet Woodruff (Galium), Bergenia and Bleeding Heart (Dicentra) are a few selections which can work well in dense shade with rich soil. Plants which thrive in the shade will be increasingly popular and necessary as suburban properties mature and the success of all the current tree planting campaigns is realized. As gardens develop, so does the adaptability of the plants within it. The gardener is the ultimate editor of the plant community and must decide which plants need a helping hand, which must be confined and what new additions could help increase the appeal of the shade garden.