|There are many members of the hibiscus family. Some are tender and tropical in nature and others are hardy landscape shrubs. Hibiscus rosa-sinensis, or Chinese hibiscus, is a frost-tender tropical plant most often grown indoors in cold-winter climates. In your gardening zone, it is hardy outdoors. The foliage is a glossy deep green and plants can grow 30' high and 20' wide.
Rose of Sharon, also known as Hibiscus syriacus or Shrub Althea, is a great shrub for late summer bloom. This is a potentially large (up to 8 or 12 foot) shrub with lovely blooms in mid to late summer. It is easy to grow, can be pruned for size in very early spring, and does best in full sun in any reasonable soil. The double flowered forms are very striking.
All Hibiscus require full sun, good drainage, regular, deep watering and frequent feeding. If you prune the plant in early spring, you'll encourage new flowering stems. If you pinch out the tips of the new growth in the late spring and early summer, flower production will increase. When you water, apply liberally to wet the entire root system. Feed plants every two weeks with a diluted liquid fertilizer (from spring through the end of summer), pinch out the the tips of the new stems and your plant should produce blooms.