Hardy Hibiscus, or Rose-mallow, is a tropical looking hardy perennial with large, showy summer blooms. Most varieties are hardy in zones 5-10 and bloom midsummer. Hibiscus coccineus, H. moscheutos and H. militaris can handle wet soil and standing water. Hardy Hibiscus can tolerate clay soil and can be long-blooming, especially if deadheaded throughout the season. These perennial flowers are attractive to butterflies and hummingbirds. Hibiscus stems should not be cut back until new growth emerges in the spring. Their winter stems can be very attractive in the landscape.