While both belong to the Tagetes genus within the Asteraceae family, French (Tagetes patula) and African (Tagetes erecta) marigolds are distinct species with different evolutionary backgrounds. Tagetes patula, the French marigold, is native to Mexico and Guatemala. Despite its common name, it has no specific connection to France. Conversely, Tagetes erecta, the African marigold, is also originally from the Americas, specifically Mexico and Central America. The "African" moniker is a misnomer, likely acquired after the plant was brought to Europe and then introduced to Africa, where it naturalized successfully. Their shared New World origin is a key botanical link, but they have diverged into separate species with unique characteristics.
The most apparent differences lie in their physical form. African marigolds are large, robust, and sturdy plants, typically reaching heights of 1 to 3 feet (30-90 cm) with a strong, upright, and sometimes woody central stem. They produce massive, pom-pom-like flower heads that are fully double and can grow up to 5 inches (12 cm) in diameter. These blooms sit prominently atop the tall stems. In contrast, French marigolds are generally more compact, bushy, and spreading plants, usually growing between 6 inches to 2 feet (15-60 cm) tall. Their stems are more numerous and finer. Their flowers are smaller, rarely exceeding 2 inches (5 cm) across, and are often semi-double, double, or crested with a more open, daisy-like appearance that sometimes shows the central disc florets.
The foliage of both species is pinnately divided and aromatic, but there are subtle distinctions. African marigold leaves are larger, broader, and a lighter green colour. They are typically spaced further apart on the thicker stems. French marigold leaves are darker green, finer, more deeply cut, and lacier in appearance, creating a denser foliage mat. The scent of the foliage is a classic marigold aroma, caused by phytochemicals like terpenes. However, many gardeners and breeders note that French marigolds often possess a stronger, more pungent scent compared to the relatively milder fragrance of African marigold foliage. This potent aroma is directly linked to their efficacy in companion planting.
From a reproductive ecology perspective, these species employ slightly different strategies. African marigolds are often grown as annuals focused on producing a spectacular, large floral display to attract pollinators from a distance. Their growth is primarily determinate, culminating in a massive bloom period. French marigolds, on the other hand, are prolific seed producers and tend to have a more indeterminate or free-flowering habit. They continuously produce a greater abundance of smaller flowers over a longer period until frost. This ensures a extended opportunity for pollination and genetic dispersal through seed, making them highly effective at self-sowing in favourable climates.
