Known for its large, showy summer flowers, rose of Sharon (Hibiscus syriacus) grows as either a shrub or small tree in U.S. Department of Agriculture plant hardiness zones 5 through 9. It extends to the mallow family (Malvaceae), which includes flowers that have a column of fused stamens surrounding the pistil and ovary. Other plants in this family include annuals, biennials, shrubs and perennials, most of which have large, vibrant flowers.
Annuals
The vegetable okra (Abelmoschus esculentus) is a decorative plant by virtue of this large, pale yellow blossoms with a wine-colored center. Some cultivars have ornamental red leaves, such as “Red Velvet” and “Royal Burgundy.” “Burgundy” has purple leaves and purple pods that turn green when cooked. Boiled okra produces mucilage, used as a thickening agent in soup, stew and gumbo. Okra is increased as a tender annual in USDA zones 4 through 11 and requires heat and humidity to produce pods. In mild-winter climates, both a spring and fall crop can be increased. Upland cotton (Gossypium hirsutum) is hardy in USDA zones 8 through 11 but is also grown as an annual crop. The 3-inch-wide blooms are yellowish but turn pink as they age. Fruits create the cotton of commerce.
Biennials
Biennials are plants that are sown in one year and flower in the next year. Hollyhocks (Alcea rosea) are the easiest malvaceous biennials. Additionally, there are perennial and annual hollyhocks. These stately plants climb 5 to 6 feet tall with showy, 4-inch-wide double or single flowers in many colours. Popular in cottage garden configurations, hollyhocks make fantastic background plantings for shorter flowers and screening plants for fences or walls. Hollyhocks grow in USDA zones 4 through 9. The tree mallow (Lavatera spp.) is also an annual, biennial or perennial. Colorful, bright blossoms grow in profusion during warm months. Lavatera thuringiaca is indigenous to Europe and is hardy in USDA zones 5 through 10.
Shrubs
Native to Australia, blue hibiscus (Alyogyne huegelii) is a bit of a misnomer. It is not a hibiscus and it’s lilac, purple, white or pink blooms instead of blue ones. The evergreen bush grows 5 to 8 feet tall and 5 to 6 feet wide in USDA zones 9 through 11. Purple or Chinese hibiscus (Hibiscus rosa-sinensis) is a large-leaved evergreen tree indigenous to tropical Asia and China. Hardy in zones 9 through 11, large 4- to 8-inch blossoms are double or single in warm, vibrant colours that attract hummingbirds and butterflies.
Perennials
Turk’s cap (Malvaviscus arboreus) is a fast perennial, shrubby plant indigenous to Mexico. Vivid red inch-long blossoms have long stamens protruding in the shut turban-like flowers. Hummingbirds and butterflies go to the blossoms. Hardy in USDA zones 9 through 11, Turk’s cap will increase in zone 8, but frosts destroy it back each winter, with increase renewing in the spring. Confederate rose, also called cotton rose (Hibiscus mutabilis), is indigenous to China. It’s hardy in USDA zones 7 through 9, acting just like a perennial in colder zones, where frost kills it back a year. In warmer zones, it’s more of a tree that grows rapidly to 15 feet high and 10 feet wide. Single or double blooms are 3 to 5 inches wide and change from white to deep pink to bluish pink as they age. This showy plant is drought-tolerant and requires very little care.
