hibiscus flower..., page-4

2. It is useful to check whether the species is on the Plants for a Future (PFAF) site for detailed information on the species, including edibility and medicinal uses http://www.scs.leeds.ac.uk/pfaf/index.html
type in hibiscus and click on the species in which you are interested. Edible species listed include:
Abelmoschus esculentus, Okra
Abelmoschus manihot, Aibika
Hibiscus acetosella, False roselle
Hibiscus cannabinus, Kenaf
Hibiscus diversifolius, Swamp hibiscus
Hibiscus heterophyllus, Native rosella
Hibiscus mutabilis, Cotton rose
Hibiscus rosa-sinensis, Chinese hibiscus
Hibiscus sabdariffa, Roselle
Hibiscus sinosyriacus, Rose of Sharon
Hibiscus syriacus, Rose of Sharon
Hibiscus trionum, Flower of an hour
Hibiscus moscheutos, Swamp rose mallow (no reports of edibility but is listed as having medicinal properties).