While both French (Tagetes patula) and African (Tagetes erecta) marigolds belong to the same genus, Tagetes, and the Asteraceae family, they are distinct species with different genetic and geographical backgrounds. Despite their common names, both species are actually native to the Americas. African Marigolds originate from Mexico and Central America, while French Marigolds are native to Mexico and Guatemala. The common names are believed to have been coined based on where early breeders in Europe developed many of the cultivars. This separate lineage is the fundamental reason for their differing characteristics in size, flower form, and growth habit.
The most striking difference lies in their physical structure. African Marigolds are large, robust plants, typically growing 1 to 3 feet tall and sometimes even reaching 4 feet under ideal conditions. They have strong, thick stems that support their massive flower heads. In contrast, French Marigolds are compact and bushy, usually staying between 6 inches and 2 feet tall. They have a more spreading and branching habit, creating a dense, mounded form. Their stems are finer and more numerous than those of their African counterparts. This difference in stature makes them suited for different roles in the garden, with Africans as backdrops and French varieties as borders or edging.
The inflorescences, or flower heads, of these two species are markedly different. African Marigolds produce very large, fully double, pom-pom-like flowers that can be 3 to 5 inches in diameter. The blooms are typically solitary on each stem and come in shades of creamy white, bright yellow, deep gold, and orange. French Marigolds, however, bear smaller flowers, usually 1 to 2 inches across. They can be single, semi-double, or double, but are often more flat-faced and crested. Their color palette is more diverse, including brilliant oranges, yellows, reds, and striking mahogany-red bicolors, often with petals edged in a contrasting color.
The foliage of both marigolds is pinnately divided and aromatic, but there are subtle distinctions. African Marigold leaves are larger, darker green, and have a more potent, pungent scent when crushed. French Marigold leaves are smaller, finer, and a lighter shade of green. Their scent is also strong and distinctive but is often described as more sharp and spicy compared to the heavier aroma of the African types. This potent aroma, caused by biochemical compounds like terpenes, is a key plant defense mechanism against pests like nematodes and browsing animals.
From a reproductive standpoint, French Marigolds are prolific seed producers and will often self-seed in the garden. They tend to flower earlier than African types and will continue blooming profusely until the first frost. African Marigolds have a longer period from planting to flowering and often have a more defined peak bloom period, though deadheading can encourage further flowering. In terms of environmental tolerance, French Marigolds are generally more heat-tolerant and can handle a wider range of conditions, including poorer soils. African Marigolds prefer full sun and well-drained, fertile soil and can be susceptible to damage from strong winds and heavy rain due to their tall, top-heavy nature.
