As in Moy Grande Hibiscus.
It's funny how once you put something into a web page (blog or otherwise), you learn that many people around the world are searching for that exact term. I posted a pic of my Moy Grande Hibiscus on my blog. Lots of people got to my blog because they were searching for that hibiscus. So, I joined them and did my own little search and learned a bit more about this flower.
The Moy Grande Hibiscus is a hybrid developed by Ying Doon Moy, a horticulturist at the San Antonio Botanical Center. (Hey! That's where I live!) He cross-bred a Hibiscus moscheutos hybrid with Hibiscus grandiflorus. The result is the largest, open-faced hibiscus flower in the world. The blooms are reported to be up to 12 inches, although many are a mere 8 - 10 inches.
We measured one the other day and it was over 9 inches!