Impatiens – Opportunity or Impasse

By Colleen O'Neill Nice

Last summer, after spending a few days out of town, I returned home to find my impatiens severely wilted. While watering them, I noticed that most of the leaves were yellow and distorted. By the next morning, the stems collapsed into a heap of yellow mush. Of course, I blamed my husband. What could he have done to my impatiens while I was gone?
A few weeks later I received an email describing the infamous impatiens downy mildew. This fungal-like organism had been attacking common garden impatiens all summer long, spreading to thirty-three states. Impatiens walleriana, both vegetatively propagated and seed-raised, were susceptible. Fusion™, Fiesta™ and Patchwork™ Interspecific hybrids with an I. walleriana parentage were also affected. Fungal spores overwinter in the soil, so if you had it last year, you very likely will again. Why not embrace this unexpected opportunity to try something new?

Your Options for Bedding and Hanging Bags

“Seed grown” annuals in flats are economical and offer endless foliage and flower color combinations. Fibrous or wax begonias are available with shiny green or bronze foliage. Keep in mind that the bronze-leaved plants prefer full sun, while the green-leaved plants thrive in partial shade. Flower colors include white, scarlet, deep rose and light pink. Wax begonias are tough and compact, bloom from spring until frost and form a solid mass of color if spaced twelve inches apart. The Garden Factory in Rochester will suggest wax begonias to their customers, as one of the many substitutes they offer for impatiens. They will continue to sell flats of I. walleriana, a very popular shade plant in our area, but they will be cutting back on the number of impatiens they grow and plan to educate both their employees and their customers about downy mildew.

“Try heat and humidity-loving torenia,” suggests Christopher Lavocat, of Lavocat’s Family Nursery. He grows the Kauai series and describes it as “a phenomenal performer in the garden.” Trumpet-shaped flowers with vivid bicolor and tricolor combinations include yellow, blue, burgundy, magenta, rose, purple and white. Torenia spreads from one to two feet, forming an eight inch tall mound. Blanketed with blooms from spring until fall, it attracts butterflies and hummingbirds. Coleus offers awesome, all-season color in a shady garden. “We grow the Fairway series in flats. They seem to be the best in our trials,” explains Lavocat. This series includes a wide range of colors, grows eight to ten inches tall and has a multi-branching habit. Be creative when planning your beds. Plant a coleus ‘mix’ in one section of your garden, then use a complimentary single-color coleus in another area. In a third bed, try two contrasting coleus to create a tapestry of color. Your garden will look and feel more cohesive with the use of repetition in both color and plant material. 

At Weeks Nursery and Greenhouse in Clarence, owner Tom Pfentner is trying something new in flats. “I will be growing the New Guinea Divine impatiens (Impatiens hawkerii ) in 32-cell flats so the larger cells can accommodate the larger root system.” Low maintenance and heat tolerant, Divine has a mounded upright habit and blooms from spring until late summer. Deep green foliage is the perfect contrast for cherry red, white, lavender, orange, light pink, violet and scarlet blooms. Pink pearl and orange bronze have green/coppery leaves. Divine grows ten inches tall and wide in partial sun to shade. PanAmerican Seed (one of the world’s leading breeders and producers of flower seed) recommends spacing plants ten inches apart in garden beds. Pfentner is also increasing his flat production of vinca (Madagascar periwinkle). According to Pfentner, “vinca has a very similar flower to garden impatiens and grows well in partial shade.” It blooms from spring until fall and is drought tolerant once established. Plants grow six to twelve inches tall and eight to ten inches wide. Colors include apricot, orange, blush, icy pink, deep pink, cherry, orchid, lilac, lavender blue, red, cranberry, ruby, rose, and white. It thrives in hot, humid summer weather, if provided excellent soil drainage.

The delicate and dainty blooms of lobelia and browallia are great options for your shade garden. “We offer both the upright and trailing Lobelia erinus in flats”, says Sally Cook, manager of annuals and perennials at Menne Nursery in Amherst. Shades of sky blue, rose, white, midnight blue, violet and lilac are enticing. Plants grow six to eight inches tall with a twelve inch spread and prefer a cool location with a north or east exposure. “Lobelia does benefit from a trim after the first flush of blooms”, adds Cook, “and thrives in evenly moist, rich soil.” Browallia speciosa is a low maintenance, long blooming charmer also sold in flats. A tidy, mounding plant, it flowers in shades of blue, deep indigo and white from June to September. Growing just a foot tall and wide, browallia requires consistent moisture (mulch is recommended) and compost-rich soil.

“Many gardeners plant their impatiens (Impatiens walleriana) in part or full sun beds,” says Lavocat, “so we suggest SunPatiens.” They have a vigorous root system which allows them to thrive in heat, without wilting in full sun or part shade. Flowers, available in myriad colors, are two to three inches wide and bloom from spring until frost. Three distinct plant habits are available and recommended for various uses. “Vigorous” is fast growing, forms an upright, V-shape and provides a mass of color in large beds. It grows three to four feet tall and just as wide. “Compact” grows in a tight mound, dense and bushy, just two to three feet tall and wide. And “spreading” recommended for landscape beds as well as hanging baskets, grows 30 to 40” tall and up to three feet wide. Since the SunPatiens are grown from cuttings, rather than seeds, they are not grown in flats. Lavocat notes, “The cost of SunPatiens is substantially more, but each plant covers the same area that eight or more walleriana would cover.”

Your Options for Containers and Hanging Baskets

In containers, window boxes, vertical gardens and hanging baskets, you can, of course, use any of the bedding plants mentioned above. But sometimes you don’t need an entire flat of just one cultivar for mixed containers. Experimenting with new colors, forms and textures can give your garden a fresh look and more flexibility. Look for annuals in four and a half inch pots, primarily grown from cuttings.

Begonias have taken the stage, front and center, with amazing trailing hybrids perfect for hanging baskets and containers. The Million Kisses series includes ‘Honeymoon’, ‘Amour’, ‘Elegance’ and ‘Devotion’ with blooms of yellow, dark red, blush pink and velvety red, respectively. Last summer, Wisley, a world-class garden in Great Britain, used award winning ‘Devotion’ extensively for their summer displays. Double blooms adorn the Bon Bon series of begonias in ‘Cherry’ or ‘Sherbet’ (pale yellow with a blush of pink). They are great performers in the garden, blooming from June through September. Bon Bon’s tolerate both hot, dry conditions and prolonged wet conditions. Self cleaning flowers are low maintenance and do not require deadheading.

Experiment with Begonia Bonfire for a profusion of exotic blooms from spring until fall. Three colors are available. Bright red-orange flowers compliment rich green serrated foliage, chocolate plum leaves highlight deep reddish-orange flowers and scarlet flowers dance above red edged, green foliage. Plants grow 20 inches tall and wide, display a rounded growing habit and can be used in garden landscapes as well as hanging baskets and containers. Bonfire blooms in full sun, partial shade and full shade. It tolerates both dry and wet weather conditions.

Create an impressive container with tropical-looking Begonia hybrid ‘Gryphon’. Large, showy, deeply serrated leaves of dark green are accented with silver-streaks. Easy to grow indoors or out, ‘Gryphon’ is water efficient and reaches two and half feet tall and wide. Try pairing it with Dichondra argentea ‘Silver Falls’ and Euphorbia graminea ‘Diamond Frost’. Gryphon also harmonizes well with Kong Coleus, Divine New Guinea impatiens, plectranthus and DragonWing begonias.

Vigorous and heat tolerant, the DragonWing series performs exceptionally well in my garden, providing drama to mixed containers and window boxes. Try these gems in your garden beds too! They have stunning, large angel wing leaves and red or pink cascading flowers which bloom continuously. They grow from twelve to fifteen inches tall with about the same spread. DragonWing begonias are not fussy or demanding and get my kudos for low maintenance. BabyWing, the compact version of DragonWing grows twelve to fifteen inches tall with a twelve inch spread. Pink or white blooms complement green foliage. New this year is a white blooming variety with deep bronze foliage.

Begonia x hybrida ‘Sparks Will Fly’ flaunts bronze foliage to showcase its tangerine-orange blooms that transition to yellow in the fall. It has a mounding habit, growing fifteen to eighteen inches tall and wide. Use this blazing begonia at the front of your border or in containers in partial to full shade. And my last begonia to extol is the big, bold and colorful Whopper series. This vigorous plant grows 34 inches tall with a 22 inch spread and flourishes with extra large flowers from spring until fall. BallSeed recommends “creating 55 MPH drive-by color” with the Whopper in garden beds or large containers. Both red and rose are available with bronze or green leaves.

Why not invigorate your shade with a redhead or two? 

Solenostemon scutellariodes ‘Redhead’ is a new coleus with bright red leaves and an upright growth habit. Maryjo Bedford of Bedford’s Greenhouse in Akron suggests “try pairing up ‘Redhead’ with ‘Wasabi’, which has brilliant chartreuse, serrated foliage. Both are durable and robust.” Also new this season is ‘Sultana’ with burgundy and lime green scalloped foliage; ‘Henna’ featuring stunning scalloped yellow-green to copper foliage with deep burgundy undersides; and ‘Mint Mocha’ with mottled, ducksfoot-shaped foliage of green, yellow and red. The preceding coleus thrive in full sun and shade, grow 18 to 28 inches tall and 16 to 28 inches wide, depending on the cultivar. “The Kong coleus with large, patterned leaves, are great for part to full shade” recommends Bedford, “where they retain their bright foliage colors. You can sustain a robust, bushy habit by pinching coleus back regularly throughout the summer.” Colors include red, scarlet, rose, mozaic and salmon pink. Plants grow eighteen to twenty inches tall and fifteen to eighteen inches wide.  

For coleus chocoholics, try ‘Chocolate Covered Cherry’ which blends a rose-colored leaf center with deep mahogany edging and lime green margins; ‘Chocolate Splash’ which spotlights chartreuse leaves with chocolate spatterings; and ‘Chocolate Mint’ which combines a rich mocha shade with mint green edges. Growing twelve to sixteen inches tall and ten to sixteen inches wide depending on cultivar, the chocolate series flourishes in full sun or shade. There is definitely a size, color and growth habit for every garden situation.

Do you need more ideas? 

The sweet potato vines are incredible in shade and Proven Winners offers a complete line for any garden situation. The Ipomoea batatas Illusion series consists of ‘Emerald Lace’, ‘Midnight Lace’ and ‘Garnet Lace’. This trio is compact, with dissected, delicate foliage in shades of chartreuse, purple/black and burgundy. They grow six to ten inches tall and trail up to four feet. Use in window boxes, containers and landscape beds. The Sweet Caroline series includes nine varieties with three distinct growth habits. ‘Bewitched’, is the most compact with an upright, mounding growth habit. It grows six to eight inches tall and trails up to two feet. Foliage is purple with serrated leaf margins. ‘Sweetheart’ has a moderately compact habit, heart shaped leaves, and grows six to eight inches tall and trails up to five feet. ‘Sweet Caroline’ has a trailing habit with three-lobed leaves and five color choices. Use these interesting vines in hanging baskets, mixed containers or as an annual ground cover in borders. They are easy to grow, vigorous and perform well in heat.

Dichondra argentea ‘Silver Falls’ and ‘Emerald Falls’ offer a truly cascading habit in hanging baskets and containers. Tiny, rounded leaves on long, delicate stems trickle down on these very drought and heat tolerant plants. ‘Silver Falls’ has a metallic look with silver green foliage, while ‘Emerald Falls’ is a clear, deep green. Just three to four inches tall with a spread of three to four feet, this foliage favorite spreads rapidly, rooting at nodes along the stems. It can be used as a ground cover in well draining beds and prefers sun or part shade.

For a whimsical blast of color, adopt Hypoestes phyllostachya, commonly called the polka dot plant. Green leaves are splashed with red, pink, rose or white. This indoor/outdoor plant grows four to eight inches tall and four to six inches wide, perfect for a sheltered fairy garden. Hypoestes prefers moist soil and can be pinched back to promote branching. Take cuttings in late summer to overwinter as houseplants.

Often mistaken for coleus, Perilla frutescens ‘Magilla Purple’ combines striking colors of green, pink and burgundy on large leaves. A vigorous grower, it fills in quickly, especially in landscape settings. Grown in sun or shade, it is low maintenance, heat tolerant and a thrilling garden performer.

Free-flowering Plectranthus x hybrida ‘Mona Lavender’ features velvety green foliage with purple undersides and spikes of dark lavender flowers. I grow this plant in part shade as a cut flower in hanging baskets and containers. The blooms are long-lasting in a vase. With an upright habit, it grows twelve to sixteen inches tall and two to three feet wide. Plectranthus roots easily, so take cuttings before frost to overwinter indoors. Plectranthus coleoides ‘Nico’ (green foliage), ‘Nicolleta’ (woolly silvery gray foliage) and ‘Variegata’ (green with cream scalloped edges) grow just eight to ten inches tall with a semi-prostrate habit spreading one to three feet. Use as an accent plant in containers or as a ground cover.

Diascia barberae, a relative of the snapdragon, is a delicate, frothy plant perfect for part shade. The Romeo series was bred specifically for hanging baskets, is vigorous and mounding. Dazzling flower hues offer a colorful display. Plants grow seven to nine inches tall and eight to ten inches wide. The compact, upright habit of the Juliet series is suitable for window boxes and containers. Just six to eight inches tall and four to six inches wide, this is another great plant for a fairy garden.

For a tropical look in the shade, try Porphyrocoma pohliana, commonly called Maracas Brazilian Fireworks. Magenta flower bracts are highlighted with purple flowers that sit atop deep green leaves embellished with silver veins. Hummingbirds love the vivid flowers on this eight inch tall and wide plant. I grow mine in a part shade, offset by the glossy green foliage of Asarum europaeum. My plants get overwintered indoors under grow lights. When flowering, they thrust tiny black seeds into neighboring pots or on the floor. Seeds will germinate at temperatures above 64˚F.

So you decide. Will you take this opportunity to try some new plants in your garden? Or will you create an impasse and continue to grow garden impatiens? According to  Bedford, “the plant breeders are asking growers like ourselves, to stop growing and selling I. walleriana. We can sell our customers healthy, disease-free impatiens, but once they get the plants home in their gardens, the disease can attack within a week or two. It can travel by wind or water splash from a neighbor’s garden or reside in your soil. We were advised that downy mildew disease could persist in the soil and air for three to five years.” The Bedford’s original strategic plan for the 2013 growing season included cutting their crop of impatiens by fifty percent. Since doing research and attending a growers’ conference, they have decided not to grow any I. walleriana. To put this into perspective for the home gardener, the Bedford’s have grown 10,000 hanging baskets of impatiens yearly, not to mention flats for bedding. “We are doing this for our customers,” they say.

Printed in the Upstate Gardeners’ Journal, March-April 2013