Impatiens care (and the downy-mildew workaround)

*Impatiens walleriana* -- common impatiens, garden impatiens, busy Lizzie -- was the dominant shade annual in American gardens for decades. Beginning in 2012, a pandemic of impatiens downy mildew (*Plasmopara obducta*) devastated plantings across North America and Europe, reducing impatiens.

Impatiens walleriana — common impatiens, garden impatiens, busy Lizzie — was the dominant shade annual in American gardens for decades. Beginning in 2012, a pandemic of impatiens downy mildew (Plasmopara obducta) devastated plantings across North America and Europe, reducing impatiens availability and confidence among gardeners significantly.

The disease changed the calculation of growing common impatiens: it is no longer straightforward to plant a bed and expect it to perform through the season. But it has not eliminated the plant, and understanding the disease and its management makes growing impatiens entirely feasible in most regions.

Zones and conditions

Impatiens walleriana is a frost-tender annual grown in zones 2–11 as a summer crop. Per Missouri Botanical Garden, it performs best in USDA zones 9–11 as a perennial; everywhere else, it is treated as an annual.

Its primary appeal is shade tolerance: it flowers freely in as little as 2 hours of direct sun, making it one of the few annuals that performs well in deep shade under deciduous trees.