Flower heads may be single or double. Plant height ranges from 6 to 18 inches. The French marigolds have a longer blooming season than the African marigolds. They generally bloom from spring until frost. The French marigolds also hold up better in rainy weather.
French marigolds are ideal for edging flower beds and in mass plantings.
They also do well in containers and window boxes. Queen Sophia and Golden Gate are excellent French marigold varieties. Varieties in the Boy, Early Spice, Hero, Janie, and Safari series also perform well in Iowa. The triploid hybrids are crosses between the tall, vigorous African marigolds and the compact, free-flowering French marigolds. Triploid hybrid marigolds are unable to set seed.