|I have started observing black spots on leaves of Rudbeckia hirta. The plant was blooming very well, however, after a week of gloomy/rainy weather, I started seeing the spots. How do I cure that? Thanks in advance.
|Answer from NGA
September 21, 2009
|Sounds like a fungal disease. Since it is so late in the gardening season I would simply leave the plants alone and cut back the dead foliage after the first hard frost. This will remove the pathogens from the garden. Next spring your plants will develop healthy new foliage.
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