Do you plant impatiens every year in your garden or containers? A popular low maintenance annual for shady areas of the yard, this year you might want to consider something else. Downy Mildew is currently wiping out plantings of this common shade annual and even causing growers to stop growing them. In my time working at a nursery I have filled many benches with flats and flats of these annuals and spent much time colour blocking them on those benches. They have always been a hot seller. But this disease has shown no sign of stopping and it will really show at your local nursery this season as I think most reputable nurseries are not even going to stock them. Sheridan Nurseries has already announced plans to not carry them this year.
Downy Mildew is a pathogen called Plasmopara obducens and only affects Impatiens walleriana and Impatiens balsamina. It does not infect New Guinea impatiens. It produces a white fluffy coating on the underside of the leaves but does not show it for 5-14 days. The plants will continue to deteriorate. There are no resistant varieties and fungicides have proven to be ineffective. And another important factor is that the fungus remains dormant in the soil and can even live there for up to 5 years. So going back to planting impatiens in a few years will cause the fungus to re-emerge.
If you are not sure if your Impatiens had them the last few years, try to remember if the plants were shorter than usual with smaller leaves and fewer flowers and had leaves that yellowed and dropped early, leaving bare stems and the whole plant went “soft” resembling frost damage. If your plants had any or all of these symptoms then your garden has been infected with Downy Mildew. Planting of more Impatiens will result in the same or worsening results.
Looks like it is time to try something new! There are lots of choices in your garden centers, here are just a few:
Some of the other shade annuals that will brighten up your garden are Begonias (Fibrous, Double and Tuberous), New Guinea Impatiens (often mistakenly called Sun Impatiens), Coleus, Lamium and Nicotiana.
Or even better, reduce the need to plant every year by going with some shade perennials instead. My favorites are Brunnera, Pulmonaria, Coral Bells, Astilbe, Japanese Forest Grass and Japanese Painted Ferns. They provide colour, seasonal interest and better yet they come back every year. These even look great in containers for the season and pop them in the ground over the winter before the ground freezes and you can reuse them in a container again or just add them to your garden the next year.
So this might be the end of the Impatiens Era but I think it will be great for people to start thinking outside the green bag and come up with some new ideas for their shady spots!