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 the drier fall weather conditions, and the fact that 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.
Hybrid marigolds, such as the Zenith series, do great in the warm, humid South.
Zinnias have a few disease problems, such as 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 and fall planting compared to 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 Dreamland series. A wide range of flower colors is available in these zinnias.
The bicolored Swizzle series zinnias has performed well in LSU AgCenter trials. The Magellan series is an industry standard. Zowie! Yellow Flame zinnia is an All-America Selection winner.
Other popular zinnia groups are the narrowleaf zinnias that include the Crystal and Star series. Flower colors available in these are limited to gold, orange and white.
The newest zinnia group includes crosses between the narrowleaf zinnias and the older zinnia varieties. These are hybrids and include the Profusion and Zahara series. Available flower colors are white, orange, cherry, fire and apricot.
Some of these are All America Selection winners. Single- and double-flower-form varieties are available in both of these series.
Zinnias and marigolds require low care and provide great satisfaction in the landscape as 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.
(For more information, contact Dr. Chris Robichaux, county agent/area horticulturist, St. Martin/Iberia Parishes, at 332-2181 or 369-4440.)