Mother Nature, the ultimate gardener, saw to it that all shrubs do not bloom at the same time. Shrubs that flower in the summer fill in a gap between the spring and fall flowering varieties, keeping the garden wrapped in color for as long as the growing season lasts.
Bluebeard (Caryopteris x clandonensis) is also known as blue-spirea and blue-mist shrub and is hardy in USDA hardiness zones 6 to 9. The shrub grows from 2 to 3 feet tall with blue-green, oval, deciduous leaves that measure from 1 to 2 inches long and blue cluster-flowers that bloom in August. Plant bluebeard in full sun and a moist, loose, fertile, well-drained soil.
Peegee hydrangea (Hydrangea paniculata) is also known as the panicle hydrangea. The plant is a deciduous shrub that grows from 10 to 25 feet tall and about the same in width. The green oval leaves grow from 3 to 6 inches long and the flowers start out as white in midsummer and change to pink and finally a rust color in the fall. The flowers grow in 3- to 10-inch long, erect clusters at the ends of the stalks. Plant peegee hydrangea in full sun or partial shade and a moist soil. The plant is hardy in zones 3 through 8.
Oleander (Nerium oleander) is a member of the dogbane family and is toxic to humans and pets. Keep the plant in an area where children and pets will not have access to it. The shrub grows from 6 to 20 feet tall with bright-green, lance-shaped leaves from 4 to 10 inches long and white, red, pink, salmon and light yellow flowers that start blooming in May and continue blooming throughout the summer. Plant oleander in bright sun and a soil that is anywhere from dry to wet. The plant is hardy in zones 8 through 10.
Bush cinquefoil (Potentilla fruticosa) is a member of the rose family. The shrub is deciduous and grows from 1 to 4 feet tall with medium-blue to dark-green, palm-like leaves about 1 inch long that turn a yellow-brown in the fall. The yellow flowers resemble a buttercup and bloom from June until first frost. Plant bush cinquefoil in full sun. The plant is adaptable when it comes to soil types and is hardy in zones 2 through 6.