Q.What Disease Is Affecting My Plants?
I’ve been growing flowers and vegetables in my garden for almost 20 years without any major problems, until now. This is the second year in a row that I tried planting Lithodora and Iceplant and they keep dying on me. The Lithodoras start out fine and grow, but then all of a sudden some of their leaves turn brown. This continues until the whole plant turns brown and dies. I have a similar problem with the Iceplants. Shortly after planting them they start to wilt and the stems turn white and shrivel up until it dies. Another plant that’s being effected is my Rudbekia. I’ve had them for about three years and this year their leaves started getting brown spots all over them until they eventually turned completely brown and crispy. I tried Googling for answers and thought fungus could be the problem so I cut back on watering and started using a fungicide (Daconil), but neither worked.
Certified GKH Gardening Expert
This does appear to be a fungal infection. All of these plants are drought tolerant, and the first two in your list will not tolerate overwatering at all. They are likely the start of the infection, and it has spread to the soil.
I would continue treating with your fungicide, as it will require constant treatment for the season to beat this one.
Another thing that you can do, during the off-season, is to solarize the area. This will kill off any living thing in the soil. Here is an article that will help: