Stars in the Shade: Impatiens

It lacks the flair of the petunia. It's not as assertive as the marigold, nor as earthy as a begonia. Yet it has increased in popularity every season for more than a decade, and it's now tops in bedding plant sales in the U.S., with growers' revenues exceeding $250,000,000 a year. It is the unassuming but cheerful impatiens.

Small wonder it's number one. Unashamedly floriferous, its blossoms come in nearly as wide a range of colors and shapes as the orchid, according to Christopher Grey-Wilson, author of The Impatiens of Africa. And it has the good manners to drop its faded petals. No deadheading needed.

Impatiens flowers from May to November, and plants continue to increase in size. I have seen an impatiens plant standing 3 1/2 feet tall and equally wide in a pot on a shady patio. Yet impatiens needs little fertilizer. It's resistant to almost all diseases and shrugs off insects, although the New Guinea impatiens is susceptible to whiteflies and red spider mites.

This versatile plant serves the gardener well in beds and borders. It drapes nicely from hanging baskets and makes a fine display in containers.

"The impatiens," says Mike Hefner, plant breeder at Bodger Seeds, Ltd., "is the near-perfect plant."

Sorting Out Impatiens

Although the impatiens is simple and unassuming, it belongs to a wild and woolly family. "The impatiens," wrote Joseph Hooker, a 19th-century British botanist, "presents so many and such different modifications of structure and is so universally and excessively prone to vary that it is a terror to botanists."

For starters, there are at least 1,000 known species, among them such interesting specimens as I. auricoma 'African Queen', a 1993 release that bears golden yellow flowers streaked with red, and I. niamniamensis 'Congo Cockatoo', with drooping orange and yellow blossoms. Or, how about I. nolo-tangere, touch-me-not, which sets bright yellow flowers with reddish brown spots that explode when they're touched, scattering their seed in all directions -- Or I. tinctoria, which is pleasingly fragrant?

Of the 1,000 or so species, only three are commonly available today: I. balsamina, known as garden balsam or, simply, balsam; I. wallerana, the common garden impatiens, known as busy Lizzie, patient Lucy, patience plant and sultana, the latter named for the Sultan of Zanzibar, to which it is native; and I. hawkeri, the New Guinea impatiens. (There is some disagreement about which botanical name should be given to the New Guineas, some preferring I. schlecteri). Actually, several plants with quite different heritages are lumped under the common name New Guinea.

The balsam impatiens usually grows as a two- or three-stemmed plant to a height of 2 1/2 feet, with white to dark red flowers tucked into the leaf axils, where they tend to be overshadowed by leaves. The plant has a long horticultural history and, according to horticulturist Joe Seals, was grown by Thomas Jefferson. It was once quite popular but never as popular as I. wallerana is today. Still, breeders are working to make it more attractive to modern gardeners.

I. wallerana is the queen of the realm today. This species grows to a height of about two feet and bears solitary or clustered flowers on short stalks that raise the flowers above the foliage. According to Ellen Leue, research director of breeding at Pan American Seed Company, there are at least 120 varieties of I. wallerana available commercially in the U.S. today. The Accent, Deco, Super Elfin and Swirl series are among those derived from this species. Recent breeding has produced dwarfer plants with heavier basal branching, giving these new varieties a pleasing, compact habit.

Most recently introduced to the trade is the New Guinea. It also grows to about two feet, but is distinguished by larger flowers, up to three inches across, and by its variegated leaves, dark gre or bronze with a yellow midrib. In general, flower types range from single to double, some as rosettes, others, camellialike. All are distinguished by a long spur -- sometimes three inches in length -- projecting from one sepal.

Colors range from red to pink, veering into the oranges or salmons, plus white and a so-called blue, which is really a lavender blue. In recent years, breeders have introduced bicolors, usually a basic color with a white star.

Separating one color from the next by name has taxed the ingenuity of seed company marketers. Try these, for example: Rose and Rose Parade; Red and Red Velvet; Salmon and Salmon Blush. Or Blue Pearl, Firelake and Twilight.

Early Impatiens

The godfather of the modern impatiens is Claude Hope. A plant taxonomist sent to Costa Rica in 1943 by Pan American, he noticed impatiens on walks through the countryside. "They were everywhere in the fencerows," he wrote, "and of all colors except white and purple. Red was not common or of especially good quality. I was charmed by them and determined to work on them at the earliest opportunity." His first crosses, made in the 1960s, were not promising. They produced a sprawling, jungly plant, about 2 1/2 feet tall, sparsely branched, with large leaves and "a flower here and there."

At about the same time, the first hybrid of merit, Imp, was introduced by Sluis & Groot, a European firm. It flowered well, but was tall with few branches. Sluis & Groot's next series, Minette, was somewhat better.

Then, in the mid-1960s, Hope used a wild impatiens to make a cross "that proved to be a real breakthrough: a dwarf, basal-branched plant with symmetrical habit, and very floriferous." He soon produced a series that had eight colors. It was named Elfin and was offered to the market by Pan American. Super Elfin followed shortly thereafter. Many of today's plants are descended from this breakthrough, including the so-called "eyed" and "blush" varieties.

In 1970, a team of USDA botanists discovered impatiens in Papua, New Guinea, with large flowers and variegated foliage. Back in the U.S., they worked with researchers at Longwood Gardens in Pennsylvania to produce the striking New Guinea impatiens, of which one of the best known is Tango, an All-America Selections winner in 1989. It has 2 1/2-inch deep orange flowers that rise above bronze foliage. Another is Little Tango, which has 2 1/2-inch flowers but grows only 12 inches high.

Growing Impatiens

Impatiens is found throughout the wetter tropics around the world, with a few temperate species native to Europe, Asia and North America. But it's a mistake to assume that impatiens needs heat and humidity. Some species have been found at elevations of 5,400 feet, others on the cool banks of streams. All commercially available Impatiens balsamina, I. wallerana and I. hawkeri do well at 60°F. Gardeners will do best by growing them in moist but well-drained soil with a pH of 6.0 to 7.0. If soil does dry out and plants wilt, a good dousing will bring them back quickly. (There is one species, I. mirabilis, with nine-inch flowers, that grows well in dryish climates.)

All like continuous shade or at least filtered light, but New Guineas will take full sun for a couple of hours in the morning if soil moisture level is kept high. Too much sun will produce heavy foliage and fewer flowers. Impatiens benefits from a balanced fertilizer but it should be used sparingly: Too much nitrogen will encourage lush foliage and prevent best flower formation.

Starting from seed is tricky. For one thing, impatiens seeds are very small; there are about 46,000 in a half-teaspoon. Also, impatiens seed loses its vigor rapidly, surviving for two years at most, even under ideal conditions. To start impatiens seeds, press them into the surface of a sterile potting mix about seven weeks before the last frost and don't cover -- impatiens needs light to germinate. After a couple of days, cover the seeds lightly with potting soil and shut out all light. When leaves emerge, move the tray back into the light.

Temperature at first should be about 75°F. Mist pots or trays intermittently until true leaves emerge. Germination takes about two weeks. Grow on at 72°F during the days, and 62°F at night.

Water plants from the garden center before you remove them from the container. Dig planting holes that are twice the size of the rootball and plant at the depth at which they grew in the container. After planting, water thoroughly.

Jamie Kitz, of Goldsmith Seeds, Inc., advises pinching out mature flowers and seedpods if you want to push the plants and keep them blooming longer. Also, pinch balsams back to one stem.

Impatiens of the Future

Although the impatiens is almost perfect, breeders are trying to produce smaller and more compact plants with more and larger flowers. And, especially, with new colors.

Several impatiens produce good yellow flowers but they are, in the words of the breeders, "reproductively isolated," that is, they do not breed well. Many produce sterile males.

Are yellow impatiens in our future? Is a true blue coming? I. decipiens, native to Nepal, bears flowers of true metallic blue. It will be collected and used for breeding one day.

Breeders also want to produce plants that will tolerate full sun and they know that I. usambarensis grows in open, sunny habitats. Finally, we can expect to see impatiens varieties that serve not only as bedding, border and container plants, but also as ground covers. Will the impatiens then be the perfect plant?

Eliot Tozer is a frequent contributor to National Gardening. He lives in Tappan, New Jersey.

Photography by Suzanne DeJohn/National Gardening Association

Impatiens of the Future

Although the impatiens is almost perfect, breeders are trying to produce smaller and more compact plants with more and larger flowers. And, especially, with new colors.

Several impatiens produce good yellow flowers but they are, in the words of the breeders, "reproductively isolated," that is, they do not breed well. Many produce sterile males.

Are yellow impatiens in our future? Is a true blue coming? I. decipiens, native to Nepal, bears flowers of true metallic blue. It will be collected and used for breeding one day.

Breeders also want to produce plants that will tolerate full sun and they know that I. usambarensis grows in open, sunny habitats. Finally, we can expect to see impatiens varieties that serve not only as bedding, border and container plants, but also as ground covers. Will the impatiens then be the perfect plant?

Eliot Tozer is a frequent contributor to National Gardening. He lives in Tappan, New Jersey.

Photography by Suzanne DeJohn/National Gardening Association

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