Why have my impatiens suddenly started to die?
Posted by Dobies Staff on 26 July 2013 10:09 am
In recent years impatiens have started to die prematurely when they are still in full flower. The foliage of affected plants turns yellow, drops off, leaving just the stems which turn black and collapse. This is due to the fungal disease Downy Mildew which is more likely to be a problem in warm, humid and wet summers. There is no chemical control available for this disease. The only thing you can do is remove any infected plants as soon as the symptoms are seen and as spores may have been washed into the soil, grow impatiens in a different area of the garden for the next two or three years. If the plants were grown in containers wash and sterilize these thoroughly inside and out and use fresh compost before replanting them with impatiens. Avoid watering late in the day as wet foliage over night will encourage the disease. Infected plants should be disposed of in the waste bin or burnt. Do not compost the plants as this would be a source of re-infection.

The  disease is not seed borne and is only spread by spores present in the atmosphere. There are no chemical controls for this disease but on our nursery we operate a stringent spray program to prevent attacks and grow the plants under hygienic conditions, to ensure that the plants we dispatch are disease free.

This strain of downy mildew is specific to Impatiens walleriana and other plants such as New Guinea Impatiens, Begonia, Gazania, Geraniums and Petunias can be safely grown in the affected area. 
(2 vote(s))
Not helpful customers