Hi We live in Central Florida and planted some Thryallis shrubs in early November. They're in unimproved sandy soil. They've been watered appropriately. Lately they've developed some black spots on the leaves. I'd love to get them healthy again, what should I do? Thank you, Carol T
This is likely a Black Spot Fungus.
You can treat with fungicides.
These links have more information.
https://www.gardeningknowhow.com/plant-problems/disease/black-spot-fungus.htm
http://bexar-tx.tamu.edu/homehort/archives-of-weekly-articles-davids-plant-of-the-week/thryallis/