Star Gardener: What, No Impatiens?

Most garden centers and nurseries on the East End will not carry impatiens this year
Begonia Baby Wing Broze Leaf

   The great rush is on to select colorful annuals for summer beds and containers. But this season may prove traumatic for the many who relied on impatiens for great swaths of nonstop color in shady areas.
    By now word is out that the popular workhorse Impatiens walleriana, including the double rosebud and miniature types, has been affected by a deadly downy mildew disease. Reality probably won’t set in until you actually go out to purchase your plants.
    Most garden centers and nurseries on the East End will not carry impatiens this year. (If you should see it in the big box stores, you would be wise to leave it there.)
    Last summer, Long Island was one of the most affected areas in the 35 states that reported it. Leaves on plants began to yellow and drop in June, with the plants dying soon after. While the origin of the disease or how long it will last remain unknown, we do know the fungus is persistent, spreads by air, and remains in the soil. In other words, it probably will be years before the disease fades or new varieties that are bred to resist the fungus reach consumers.
    To learn more about downy mildew disease on impatiens and see photographs, look at the Suffolk County Cooperative Extension Web site, ccesuffolk.org/floriculture-program. The information was updated in mid-March by Margery Daughtrey, a plant pathologist, and Nora Catlin, a floriculture specialist.
    This summer is likely, therefore, to be a time of experimentation and an opportunity to look for colorful combinations of new annuals for shady locations. You should expect to pay more — a lot more — as the alternatives are mostly grown from cuttings and available only in individual containers, not flats. However, most of these plants are larger than impatiens so they can be spaced further apart and fewer plants would be needed.
    Local garden center and nursery people recognized early on that they would have to do more hand-holding and educating than in previous years; print material should also be widely available. Please remember: This is the busiest time of year at garden centers so try to be patient. If at all possible avoid weekend shopping; it will be a lot easier to get guidance during the week. You’ll probably get better service if you educate yourself a bit first. 
    The main question is: What are good alternatives to impatiens? Unfortunately there is no easy, simple answer. If you are one of those who planted your impatiens in partially sunny or sunny locations, you are in luck and can use New Guinea impatiens or SunPatiens, a new hybrid with New Guinea impatiens as one parent. There is a compact form called Viva! SunPatiens that should grow no taller than 24 inches. If planted in too much shade, SunPatiens needs to be clipped back by mid-summer to prevent its becoming leggy. A different alternative are the vincas, which resemble impatiens and are sun lovers.
    Nora Catlin of the Cornell Cooperative Extension also revised a helpful list of annuals in mid-April for partial shade that is available on the Internet at ccesuffolk.org/assets/Floriculture/Impatiens.
    In shade, wax begonias are the best and most reliable performers for bedding plants, especially if you want white flowers. A number of new hybrids, with series names like Big and Whopper, have been referred to as begonias on steroids and should be widely available. They are either white or various shades of pink.
    Torenia is a shade-loving annual that comes in a range of blues, purples, and lavender as well as rose, cream, and white. Donald Horowitz of Wittendale’s has grown torenia for a number of years and recommends it for moderate shade. They are low-growing, trailing natives. Some literature says deer do not eat them. 
    The colorful foliage of coleus can be terrific in mass plantings, but unfortunately some varieties are subject to coleus’s own downy mildew disease. It will take some years of experimenting to identify those cultivars that are resistant. That southern favorite Caladium is also good in shade, although I recollect deer were attracted to the white leaves the year I tried it. But there is very little deer won’t graze on or eat, isn’t there?
    “There are enough challenges,” Mr. Horowitz said. “Why guarantee failure?” he asked, referring to impatiens. “We want people to have success,” he said, an expression almost every garden center person I spoke with echoed.