Are all hibiscus flowers edible?

I have been drinking hibiscus "tea" and love it. I am wondering if my hardy hibiscus (mallow) plants are edible. I live in northwest Indiana so I can only grow hardy varieties outside. I spoke to someone who grows tropical hibiscus and she thought that probably all of the mallow family were edible so probably mine were but she did not know for sure because they did not grow the hardy varieties. My bushes make so many giant flowers that we just pick up and throw away and I would love to make "tea" from but I do not want to take a chance on something I don't know that might be poisonous or make me sick. Does anyone know the answer to this?

Is there a difference between rose of sharon and the hibiscus plants grown in florida? when i lived in PA we grew plants that were called rose of sharon and now i live in FL and everyone says hibiscus. the flowers seem to look the same and the botanical name of rose of sharon starts with hibiscus. just wondering because I want to grow a particular variety of rose of sharon seed i brought with me and don't want it to cross with my neighbor's hibiscus bushes via pollinators. I also was wondering about harvesting for tea because i drink it daily. thanks.

Hibiscus sabdariffa, has edible calyxes that can be dried and used for tea. Also known as roselle, red sorrel and flor de Jamaica, Hibiscus sabdariffa is the hibiscus most commonly used for tea and is used in many areas of the world. Hibiscus rosa-sinensis, an ancestor of the modern hibiscus plant, is also used for tea. Most parts of hibiscus plants are edible and that the flowers make a sweeter tea, while the leaves make a tea that is more astringent.

thanks. I am fine closing post if others are.

I am really wanting to know if there are ANY hibiscus plants/flowers/calyxes that ARE NOT EDIBLE whether they are hardy types or tropical types. I would like to use the hardy ones in my garden but I don't want to try them if they are poisonous. I can't seem to get a definitive answer. Thanks to anyone who can help in this matter.

You may find this page helpful.
Some good links to read on it.
http://www.hibiscus.org/toeat.php

Seems Rose of Sharon might be poisonous to dogs, from internet:
" While the Rose of Sharon is specifically named by the ASPCA as being toxic to dogs, other species may cause toxic reactions as well, especially the flowers, although poisoning is usually mild. For safety's sake, keep your hibiscus plants, both inside and outside, away from the reach of your pooch."

Toxic to dogs?
https://homeguides.sfgate.com/toxic-tropical-hibiscus-dogs-82293.html

Though contrary to many other sites that say the ASPCA say it is poisonous, the ASPCA at least on this page says no.
https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/hibiscus