Answer: This plant (Sutera cordata) needs to be kept moist, but should still be in a well drained mix so the roots are well aerated. The pH should be about 6.0 to 6.5. It has some tendency toward pythium, so perhaps this is what you are seeing especially if the soil is overly wet or the plants are crowded so there is a lack of air circulation. Finally, this plant flowers best in cooler temperatures (73 degrees or less) and often ceases bloomin gin hot weather so it is possible that severe heat is just taking its toll.
Q&A Library Searching Tips