Shady Solutions for the Impatiens Downy Mildew Disease

Have you heard about the new disease that’s wiping out impatiens across the country? Known as “impatiens downy mildew,” it can wipe out a drift of these summer annuals in short order.

We experienced it last year and learned more about it from Sally Roth. We turned to Rick Schoellhorn, the former director of new products for Proven Winners. Rick was responsible for the evaluation of all plants being considered for the Proven Winners line. Here’s what he told us:

Impatiens downy mildew.jpg5 Annuals to Plant Instead of Impatiens

Impatiens downy mildew (Plasmopara Obducens) has become a problem across the United States, killing annual impatiens (also known as busy lizzie, or touch-me-not). The symptoms of the disease are white fuzzy patches under the leaves, followed by leaf drop and slow death for the plant. What can you do? Select other plants to take the place of impatiens in your yard until this disease relaxes its hold on American gardens. Like every epidemic, it is likely to come and go. It’s possible that you will never see it in your yard, but if you do, here are five great options for replacing impatiens in your shade gardens this summer:

 

Torenia.jpgTorenia

The series of Catalina and Summer Wave Torenia make great part-shade color and mix well with other shade annuals. In hanging baskets, they add a trailing component as well as constant color through the summer. They can also be used in mass plantings, as shown in the photo below.

 

New Guinea Impatiens

The simplest substitution, and not susceptible to downy mildew. New Guineas are Impatiens hawkeri; the varieties affected by the disease are Impatiens walleriana. Although New Guinea impatiens won’t thrive in deep shade, they do fine in part shade and full sun.

Add color with foliage: Coleus can be used in mass plantings or to highlight other shade flowers. The ColorBlaze series is easy to grow.

Resistant Impatiens at downy mildew.jpgThis combination features New Guinea impatiens, a type of impatiens that is not affected by the disease.

Featured plants: Infinity White New Guinea impatiens, variegated sweet flag (Acorus gramineus), white licorice plant (Helichrysum petiolare) and Green spice heuchera. Photos: Courtesy of Proven Winners)

 

Oxalis.jpgOxalis

Trouble-free and easy to grow, these clovers make wonderful shade plantings in both containers and the landscape. Dark foliage and small white flowers provide season-long color. Tolerant of full shade.

 

Begonias

Begonias are available as bedding types and tuberous types, such as the Nonstop series and the Illumination series. They will thrive in full-shade and part-sun gardens and planters.

 

Blue-flowered Torenia.jpg

Blue-flowered Torenia combines with chartreuse coleus to mark the edge of this shady bed.

 

Red-flowered angel wing begonias.jpg

Red-flowered angel wing begonias mix with coleus in this shady border.

Last updated: 03/14/2024