One of the garden’s most common bedding plant has plenty of exotic varieties that are easy to grow and are disease resistant

I am not sure whether it’s because when times are tough we often gravitate toward nostalgia, but as I browse the seed catalogues this winter, I am thinking wistfully about busy lizzies. This lush, free-flowering, easy-to-grow genus from cool, highland rainforests was once one of the most common bedding plants for shady spots. Yet in the past decade an outbreak of a new and deadly fungus-like disease – impatiens downy mildew – led to a collapse in demand for these plants.

Deadly as it is, the disease appears to be extremely species-specific, centred squarely on Impatiens walleriana, which made up probably 99% of the market. Discovering this, plant breeders worked to create new varieties by crossing the susceptible species with other close relatives to create plants with a much higher genetic resistance. As a botanist, I do wonder: why the over-reliance on a single species? There are about 1,000 species of impatiens, many of which are far more striking and exotic-looking, and just as easy to grow. Rather than a disaster, could this be a much needed spur to open our eyes to a huge diversity of possibilities that we have been missing?

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