Many of my Shasta daisies have a similar problem, and I'm looking for help. Some of these plants were purchased early in the year, and they were blooming much earlier than those that came up naturally. They are different varieties; Becky, Banana Cream, Daisy May, and White Mountain.
Basically, the plant looks healthy with abundant blooms, but then the plant turns brown and dies back. I'll attach a photo, to give you an idea. If you look closely, you can see the new (green) growth at the soil line.
Is it possible that they have spent their blooms (because they were grown early for retail) and are just dying back?
I did fertilize them with milorganite, and wonder if perhaps that is the cause (?).
Thanks in advance for your help