Foliage First
Refining the Shade Garden
By Rachel Foster 9/9/04

Some people have trouble coming to terms with shady gardens. Gardeners who revel in big splashes of floral color and a jungly tropical look may never be content with the woodland mood, which leans toward restfulness. I won't try to pretend otherwise. But I will insist that shady gardens don't have to be dull. In fact I think a distinct quiver of excitement runs through the best shade plantings.
There are, of course, different degrees of shade. Areas receiving shade only in the afternoon, or getting lightly filtered sun on and off during the day, are ideal for many plants. Dim places under big conifers where you'd have difficulty reading a book are, on the other hand, nearly impossible to plant. In between is real shade gardening territory, but be prepared for lots of trial and error if you want to maximize the variety of plants you grow. Increase the odds in your favor by improving your soil: a crumbly texture combined with good drainage and a high organic content will suit the greatest variety of plants. Fall is a great time for soil renovations.
Where there's an existing canopy, don't plant too many trees and shrubs beneath it. They tend to obscure beautiful tree trunks and make the ground even shadier. Since you may have few woody plants, choose them carefully. In low light, leaves are more widely spaced and their shape is easier to appreciate. Among shrubs and small trees with pleasing leaf shapes, maples excel. One of the best maples for small spaces is the golden full moon maple, Acer shirasawanum ['Aureum.'] Unusual cultivars of our native vine maple include 'Monroe,' with deeply dissected leaves.
Some rhododendrons are worth growing just for their leaves. 'Sir Charles Lemon' can be slow to produce its pure white flowers in any location, but few gardeners complain: over wintering buds are red and the leaves have bright, rust-colored undersides. Lower growing Rhododendron pseudochrysanthum has new leaves heavily dusted with silver, and in the best forms (such as 'Ben Nelson') the leaves have cinnamon-brown felt underneath. New leaves tend to stand upright, which shows this off nicely.
I like to give the larger plants in shade beds lots of space so neighbors don't have to compete for light. Lower, ground covering plants fill the spaces in between, but ground cover doesn't have to mean a uniform carpet of something dull and invasive. A tapestry of plants of medium vigor, such as London pride, Epimedium grandiflorum and variegated ajuga, is a better solution for a bed of mixed herbaceous plants. (London pride is a common name applied to two rosette-forming saxifrages with a tough constitution, Saxifraga umbrosa and S. x urbium. Both spread by short runners to form neat patches.)
Where summer flowers are few and far between, contrast in shape, color and size of foliage is what keeps things interesting. Leaf colors other than green tend to fade in full shade. Yellow leaves turn chartreuse, which is often an improvement, as in golden feverfew. Lovely striped Hakone grass (Hakonechloa macra 'Aureola') looks prettier in shade. It is a perfect companion for the big, shapely but somber leaves of Lenten roses (Helleborus x hybridus).
Where trees make the ground both dark and dry, any brightly variegated plant that will grow there is worth its weight in gold. Gladwin iris (Iris foetidissima) is a bit of a weed, but the variegated form makes few seeds in my garden and is possibly the boldest plant you can grow in deep shade. Its two-foot clump makes a striking feature rising out of ground cover or punctuating a hellebore planting. Hostas with white variegation are effective too. Try planting them in tubs and pots if slugs and snails defeat you; it also circumvents the problem of root competition.
Evergreen ferns are valuable for their year-round presence. They are more deer resistant than deciduous ferns, and come in a huge variety of forms. But deciduous ferns have a fresher color and an airy look that really gives the garden a lift. Delicate western maidenhair fern (Adiantum aleuticum) is a good choice for places sheltered from wind. Find a foreground spot for Japanese painted fern (Athyrium nipponicum 'Pictum'). It's more compact than most deciduous ferns, and deserves a place where it can be examined closely: the leaves are a mélange of lavender gray, dark red and silver.
Excitement comes in many forms, including the weird and unusual. The calla-lily family includes not just arums and skunk cabbage (dramatic, but needs ample moisture!) but shade-loving arisaemas. Call them Jack-in-the-pulpit if you prefer. They range in height from 10 to 48 inches, with most somewhere in the middle of the range. Jacks sport a few dramatic leaves and a dark, bract-like spathe, usually striped or mottled, enclosing minute flowers at the base of the rod-shaped spadix. Almost more bizarre are certain podophyllums, relatives of the North American mayapple. The oddly geometric leaves of Japanese P. difforme are held up like small umbrellas heavily marked with pale green and purplish black. There's nothing else quite like it. It stops people in their tracks.