Seeds from Hibiscus laevis. The halberd leaf rosemallow, is a herbaceous perennial flower native to central and eastern North America. This Hibiscus can grow up to 5 feet. Bloom time is July, August and September. Their showy, creamy white or pink flowers are large, up to 6 inches across, and are hard to miss. These flowers require exposure to sunlight to open up properly, and then last only a single day. Hardiness Zone 4 to 9.