BOSTON (CBS) – The common impatiens that New Englanders have used as a staple in their gardens are in danger!
Downy mildew, a disease that affects the common impatiens, Impatiens walleriana, was first diagnosed in 2004, and was observed in Massachusetts in 2011. In 2012 the disease became widespread and destructive. Unfortunately it is projected to be even worse in 2013.
Downy mildew thrives in moist conditions, such as on wet foliage and in dense plantings, and is very contagious. Its spores spread short distances by the splashing of water,and long distances when they detach and become windborne. A second type of spore, resting spores, are produced inside the stems of infected impatiens and are released into the soil where they can survive through the winter and infect new impatiens planted in the same beds the following year.
It’s hard to believe that the #1 annual Americans have loved for decades is in such danger, but to date there is no cure. If you see the beginning symptoms of downy mildew, including yellowing or striping on leaves or white downy growth on the underside of the leaves, remove the entire plant, roots and soil, and destroy it (do not compost it!). Fungicides can work as a preventative measure but are not a cure and are not recommended as a treatment on impatiens identified with downy mildew.
The good news is that downy mildew only affects impatiens walleriana and rosebud impatiens, so you don’t have to leave those garden beds empty. The growing division of Mahoney’s Garden Centers and other growers have greatly increased the amount of plants they’ve grown as alternatives to impatiens. SunPatiens are a relatively new series of impatiens that not susceptible to downy mildew and uniquely love both the sun and the shade. New Guinea impatiens, begonias and torenia are other flowering shade-tolerant alternatives. For some great foliage and texture options, choose from various coleus and caladium varieties.