Tropical Hibiscus, Hibiscus rosa-sinensis: Tropical hibiscus grows permanently in the landscape in warmer U.S. Dept of Agriculture zones 9 through 11, unless they are taken indoors in winter. Outdoors, one freeze – below 25 degrees Fahrenheit – will kill them A hibiscus flower usually has five petals (a single hibiscus).
Recently I purchased four new tropical hibiscus plants. Two plants have bright, sunny yellow single hibiscus flowers which is a first for me.