Synonyms for Flower-of-an-hour:

n.

flower-of-an-hour (noun)
Black-Eyed Susan, Bladder Ketmia, flowers-of-an-hour, Hibiscus Trionum.
plant (noun)
Black-Eyed Susan, Bladder Ketmia, flowers-of-an-hour, Hibiscus Trionum.

Other synonyms:

Hibiscus trionum
Hibiscus Trionum.
black-eyed susan
Black-Eyed Susan.