Lousiana's hot, humid summers and mild winters make for lush landscapes with many choices. The state is defined as zones 8 to 9 in the U.S. Department of Agriculture Plant Hardiness Zones, and temperatures may dip below freezing occasionally. Azaleas are among the most common of Louisiana landscape plants, but many colorful flowers and trees dot landscapes throughout the state.
Nearly ubiquitous around south Louisiana, azaleas (Rhododendron) offer evergreen color and bright, early spring blooms. Azaleas, hedge plants, can grow to 20 feet tall. The Florida azalea (Rhododendron austrinum) is a selection that grows to 10 feet and has fragrant blooms in pale yellow, cream, pink, orange or red. Particularly in the hot Louisiana summer, azaleas prefer partial shade and moist soil. Azaleas are available in many sizes, and the larger varieties are particularly good screening plants that can be used in front of a wall or to enclose a landscape. Use smaller varieties in gardens as a backdrop to plants that flower in summer or fall.
Also known as swamp irises, Louisiana irises thrive in wet areas, such as near bayous or ponds or well-watered gardens that have afternoon shade. These irises are native to the Gulf Coast and have fairly flat blooms on individual stems that can grow to 5 feet. Swamp irises bloom in the spring and are available in a rainbow of colors. Among the more well-known varieties are the copper iris (Iris fulva), which grows to 3 feet and has red-copper blooms, and the giant blue iris (Iris giganticaerulea), which can grow to 6 feet and has blooms that range in color from white to blue. As this iris is an early bloomer, it provides height and color variation with lower-growing, summer- or fall-blooming annuals or perennials.
Oriental magnolia (Magnolia denudata) is also known as the Yulan magnolia and is considered, according to the LSU Agricultural Center, one of the most spectacular species of magnolia. This tree blooms in February with showy, fragrant, tulip-shaped flowers that are pale pink to purple on the outside with white centers. A deciduous tree, the Oriental magnolia loses its leaves in winter but is long-lived. The Oriental magnolia can grow to 35 feet and prefers full sun and well-draining soil. This tree will bring early color to any landscape and may be used with evergreen trees or those that bloom in other seasons. The Oriental magnolia also provides shade.