Usually, my Hibiscus has dropped its leaves by now. I don't think it knows the date. The Hibiscus bloom stays open for 1 day, closes and falls off. I noticed a small little timer at the base of the plant which controls this. This bloom started opening yesterday evening and will close to fall off today.
The average Hibiscus owner pays little attention to the small timer that comes with each plant. It insures the blooms to last within their allotted time which is one day.
I briefly mentioned this feature in my original post (above).
I thought it extremely necessary to all future Hibiscus growers to have this information in front of them upon planting and maintaining their garden correctly.