Q.What Is Wrong With My Black Eyed Susan I Just Planted
The plants are green but droopy with leaves starting to curl on one

Certified GKH Gardening Expert
This may be a case of overwatering. They will require some time to dry out, at least, down to two or three inches between waterings. As a preventative, I would try using a fungicide. These articles will help:
https://www.gardeningknowhow.com/ornamental/flowers/black-eyed-susan/black-eyed-susan-flower.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/ornamental/flowers/black-eyed-susan