The common name for the annual flower genus Tagetes, often planted to deter pests, is marigold.
Tagetes belongs to the daisy family, Asteraceae, and includes roughly 50 species of annual and perennial plants. Gardeners commonly grow African marigolds (Tagetes erecta), French marigolds (Tagetes patula), and signet marigolds (Tagetes tenuifolia). Their pungent scent and root-released compounds help explain their long-standing reputation as companion plants.
The name marigold is also used for Calendula officinalis, the European pot marigold, so the common name can occasionally cause confusion. Calendula and Tagetes are different genera, although both have yellow or orange flowers and belong to the same broader plant family.
Tagetes species originated mainly in Mexico, Central America, and parts of South America. The Aztecs cultivated them for ceremonial, decorative, medicinal, and practical purposes. In Mexico, Tagetes erecta remains closely associated with Día de los Muertos, when its vivid flowers are used on altars and graves. Marigolds can discourage some insects and soil pests, but their protective effect depends on the species, cultivar, and pest involved.