USDA hardiness zone 9 includes parts of Oregon, California, the Gulf coast of Texas and Louisiana and central Florida. Summers in zone 9 are hot and often humid, and winters are mild, but with occasional winter freezes. Flowering shrub varieties are abundant in zone 9, with many options available to the home gardener.
Butterfly bush (Senna bicapsularis), also known as Christmas senna, is an upright, evergreen shrub with a sprawling form. Butterfly bushes reach a height and spread of 12 feet and grow rapidly. Butterfly bushes have compound leaves--6 inches long, with 6 to 10 leaflets opposite on each leaf. Butterfly bush is often multi-stemmed and has showy, bright yellow, ½-inch flowers in clusters of 4 to 8, blooming in October or November. Grow butterfly bush in full sun on a wide range of soils.
Hibiscus (Hibiscus rosa-sinensis), as known as Rose-of-China, is a large, up to 20 feet tall, evergreen shrub with a rapid growth rate. Hibiscus leaves are glossy-green, with serrated edges that are up to 6 inches long. Hibiscus flowers are bell shaped, 6 inches wide and very showy, ranging in color from white, red, yellow or orange that bloom in warm weather. Grow hibiscus in full sun to partial shade on slightly acidic, nutrient rich soils.
Hydrangeas (Hydrangea macrophylla) are quick-growing, rounded, symmetrical, deciduous shrubs, growing up to 8 feet tall and wide, but often seen 3 to 5 feet tall. Hydrangeas have thick, simple, 9-inch leaves and large, showy clusters of flowers called cymes. Hydrangea flowers are white on neutral soils, pink on alkaline soils and blue on acid soils. Grow hydrangeas in partial or moderately deep shade, on nutrient-rich soils.
Kurume azalea (Rhododendron X obtusum) in an evergreen shrub, growing 4 to 6 feet tall and wide with a slow growth rate. Kurume azaleas have simple, 1-inch, elliptic leaves and come in many colors, ranging from white, pink, red, salmon and lavender, with a funnel-form, 1½ inches long, in clusters of 2 to 6 flowers. Grow kurume azalea in partial shade, on nutrient-rich, well-drained, acidic soils.
Gardenias (Gardenia augusta) are evergreen shrubs with a moderate growth rate, often seen 3 to 4 feet tall. Gardenia leaves are 3 inches long, dark green and arranged in whorls of 3 and have very fragrant, white, waxy, 3-inch flowers, blooming in spring and summer. Grow gardenia in full sun to partial shade, on nutrient-rich, acidic, well-drained soils.