Hibiscus (Hibiscus spp.), in all its varieties and forms, grows in full sun and produces large, funnel-shaped flowers with soft petals and attractive large stamens. The flowers come in a range of colors, some with veins of different colors toward the center. If your climate doesn't allow you to grow hibiscus outdoors, you can still enjoy them in large containers that spend summers outdoors and winters indoors.
Hibiscus has some of the largest flowers of any plant. Rose mallow (Hibiscus moscheutos) produces the largest flowers of all hibiscus from late spring until the first frost, with some reaching 1 foot across. Flowers on the Chinese hibiscus (Hibiscus rosa-sinensis) come in single or double forms and can be 4 to 8 inches wide. Rose mallow thrives in USDA plant hardiness zones 5b through 11 and Chinese hibiscus in USDA zones 8a through 11.
Hibiscus rosa-sinensis has been cultivated for centuries in tropical Asia and is honored as the national flower of Malaysia. It grows up to 30 feet tall in warm tropical climates like Hawaii, but up to 15 feet tall in the U.S. mainland. This tropical hibiscus features single or double flowers in a full range of colors.
Two hibiscus are native to Hawaii, but only one has been named the official state flower: Hibiscus brackenridgei. This hibiscus grows as either a shrub or a tree and produces pure yellow flowers with red veining near the center and a prominent yellow stamen. It grows to 15 feet tall and 8 feet wide in USDA plant hardiness zones 10a through 11.
Resembling a bouquet of hollyhocks, rose of Sharon (Hibiscus syriacus) grows as a deciduous shrub up to 12 feet tall and 6 feet wide in USDA plant hardiness zones 5b through 11 and can also be trained into a single trunk with a treelike top or as an espalier. An evergreen tree hibiscus (Hibiscus tiliaceus) is native to tropical Asia and Polynesia. It grows 30 feet tall and wide in USDA zones 10b and 11 with 4-inch flowers that open yellow in the morning and deepen to orange by the end of each day.