I don’t dislike impatiens. They offer constant bloom and color in gloomy corners of the yard. But I avoid planting them by the hundreds. If I wanted my garden to look like a chain hotel parking lot, I’d settle for a sign that says “Lock Your Car.”
There are other shade annuals out there, and it’s okay to mix them up. It’s even all right to mix them with perennials or tropicals. You don’t have to worry about frost until around Halloween. Make the most of it.
People who like to make plant compositions in containers refer to the three distinct roles of their combinations: thrillers, fillers and spillers. The first are upright specimens, the last the plants that trail over the rim of a pot, and the fillers everything else. The same design principle can apply to garden beds. And impatiens, for all my playful bashing, function well as fillers.
As you prepare your summer shade garden, think about plants whose primary ornament is their foliage. Here are a few of that work well in the Washington garden.
Forget the bedding wax begonia. New varieties are grown as large foliage plants and work well as thrillers in small beds or containers, or as fillers in the shade garden. Gryphon, available since last year, has maple-like leaves, variegated green-black and silver, and with marked red veins. It would work well paired with “anything with silver tones: oranges, purples,” said Bill Calkins of Ball Horticultural Co., its breeder. “It makes a neat thriller in the middle of a combination.”
Dragon Wing is a begonia with dark, glossy green leaves and scarlet flowers and is widely admired for its ease of cultivation and vigor. Among the cane begonias, it’s bulletproof. Angel Wing is an older type, though still a bold begonia. The late discerning plantsman Wayne Winterrowd favored the classic pink-flowering cane begonias President Carnot and Irene Nuss.
The world of coleus has exploded in the past 10 years with leaf colors and patterns to fit any combination or color scheme, hot or cool. If you can’t find a coleus that works for you, you’re just not trying. Some have golden or amber foliage, others lime green, yet others deep russet with acid-green margins. Just think about color combinations when choosing, and count on plants growing to as tall as three feet by September. Pinching stems will promote a compact, bushy habit. In a shade garden, avoid varieties for full sun.
Caladiums, like coleus, are an old-fashioned tropical enjoying a revival. This popularity has spawned new introductions. Caladiums are valued for their variegation, striking vein patterns and the way the markings change as each leaf develops and grows. As with other showy foliage plants, varieties with white or light pink variegation are useful in the shade garden for lightening dark areas and projecting the garden in the evening. I love types with thick leaves and generous red centers, such as Florida Cardinal and Red Flash.
Another huge, arrow-leaf tropical, these outsize varieties can produce leaves whose midveins extend several feet. If you want to scale back the size but not the intensity, look for the dramatic, white-veined alocasias and colocasias, varieties such as Amazonica, Freydek and Illustris.
A few more foliage plants
Several canna varieties with dark and variegated leaves make great foliage plants, though the desired markings darken in too gloomy a spot. Tropicanna started the craze, now joined by Tropicanna Gold and Tropicanna Black. Strobilanthes, or Persian Shield, has striking, pointed foliage that looks almost metallic: magenta-purple with marked, decorative venation. As with coleus, this grows to three feet or higher and should be pinched back to promote bushiness and fresh growth.
Diamond Frost is a lacy, white-flowered euphorbia that will bloom happily in partial but not deep shade. Its wild popularity in the past five years has spawned several similar varieties, including Breathless White and one with pink accents, Breathless Blush.
Foxtail fern has fluffy, acid-green fronds but is a flowering plant related to asparagus, not a fern. Its fine texture and bright green color add a lot of vitality to shaded beds and containers.
The pink-speckled polka-dot plant (Hypoestes) is now a common houseplant that works in the summer shade garden, said James Gagliardi of the American Horticultural Society. “They play well off a New Guinea impatiens,” he said, “and create a bold look in a big area.”
Hardy perennials offer the bonus of coming back year to year, but there is no law against using them in a broader display of seasonal plantings. Certain brunnera varieties offer silver foliage that persists after the delicate blue flowers of April have passed, though they are not a plant for dry shade. Both Jack Frost and Looking Glass have silver, heart-shaped leaves. Chinese ginger (Asarum splendens) is a low-growing woodland foliage plant with eye-catching silver markings on its heart-shaped leaves. Hakone grass is now familiar but not trite, with lovely mounding clumps that have real grace and presence in the partial shade garden. The golden form pops particularly nicely and can be used in combinations of yellows and blues.
Hostas, diverse in size, color and use, reward thoughtful placement in the shade garden. The big-leafed sieboldiana varieties work as supreme thrillers, though the small- to medium-size varieties are better suited to smaller gardens and massing. I’m a big fan of Emerald Tiara, a narrow-leafed, chartreuse and green variety, as well as the stouter, more upright Krossa Regal, with its distinct blue cast.
Hardy begonias bloom in August, and the seed capsules remain showy into the fall. They emerge in early summer as small-leafed plants but just keep coming. They look tropical and the leaf veining is striking, especially when backlit.
Gagliardi likes to use a low-growing, small-leafed but vigorous yellow-green perennial named creeping Jenny (Lysimachia nummularia Aurea) as an attractive spiller. It grows vigorously in moist conditions.
If you can meet their moisture needs, both tender and hardy ferns are great for containers or beds. Japanese painted ferns, which are hardy, provide dazzling silver fronds that are both showy and elegant. The maidenhair fern has fronds arrayed proudly on tall, dark stems. It adds fine texture and grace to the moist shade bed. Both hardy and tender species are available.