Marigolds are great fall flowers and attract pollinators to the garden. (Photo by Allen Owings)

The bicolored flowers of Swizzle zinnias are eye-catching in the landscape. (Photo by Allen Owings)

News Release Distributed 08/01/14

By Allen Owings
LSU AgCenter horticulturist

HAMMOND, La. – Marigolds and zinnias for fall flowers? Yes! We often associate many of our warm-season bedding plants with the spring and summer growing seasons. Often overlooked is the fact that many of these plants may actually do better in our Louisiana landscapes during mid- and late summer through fall. Zinnias and marigolds are two excellent examples of warm-season bedding plants to try from August through the first killing frost.

Marigolds are a great fall-blooming plant. They produce bold colors and striking flowers and are great for fall landscape displays. Many marigold plantings in the late summer and fall will actually outperform a spring planting in terms of lasting in the landscape.

Most spring-planted marigolds usually decline considerably by June in Louisiana due to petal blight, falling over – particularly African varieties – and spider mites. An August planting typically does not experience the flower disease due to drier fall weather conditions, and spider mite problems are less at this time of the year.

Marigolds come in a wide range of varieties. African marigolds are taller, larger, cut-flower-type varieties. Primary colors are orange, gold and yellow. Examples include the Inca II, Perfection and Antigua series. New series are the Taishan and Moonstruck varieties.

French marigolds are the shorter, smaller-flowered types and include the Hero, Bolero, Bonanza, Janie, Durango and other series. French varieties offer more color variation. The new Cresta and Alumia series from Floranova are doing very well in LSU AgCenter trials in Hammond. Hybrid marigolds, such as the Zenith series, do great in the warm, humid South.

Zinnias have a few disease problems – primarily leaf spots (caused by fungus and bacteria), flower and petal blight, and powdery mildew. Like marigolds, these problems can be greatly reduced and plant performance can be improved with a late summer or fall planting compared with a spring planting.

We have many zinnias at our disposal.

The traditional older zinnia varieties we grew up with are the Zinnia elegans varieties. Some of these varieties are good for cut flowers, like the Benary Giant series, while other varieties are better as short-growing bedding plants, such as the large-flowering but smaller-growing Dreamland series. A wide range of flower colors is available in these zinnias. The bicolored Swizzle series zinnias have performed well in LSU AgCenter trials. The Magellan series is an industry standard. Zowie! Yellow Flame zinnia is an All-America Selection winner.

Narrowleaf zinnias include the Profusion and Zahara series. These are the varieties being planted in the largest numbers today. These are hybrids. Available flower colors are white, orange, cherry, fire and apricot. Some of these are All-America Selection winners. Single- and double-flower varieties are available in both of these series.

Zinnias and marigolds are easy to grow from seed, but garden centers still carry transplants in late summer and early fall. Zinnias and marigolds require low care and provide great satisfaction in the landscape as the long, hot days of summer fade to cooler, shorter days of fall.

Remember that bed preparation is important as it is for all bedding plants. Plant these selections in full sun for best results.

You can see more about work being done in landscape horticulture by visiting the LSU AgCenter Hammond Research Station website. Also, like us on Facebook. You can find an abundance of landscape information for both home gardeners and industry professionals at both sites.