Achenes ripen and are shed within two weeks of the start of bloom. The heads contain mostly hermaphrodite (having both male and female organs) florets and are pollinated primarily by beetles in the wild, as well as by tachinid flies and other insects. The leaves of all species of marigold include oil glands. The oils are pungent.
Used mainly as an edging plant on herbaceous borders, it is a low-growing plant with flowers of blended red and yellow in most varieties. French marigolds are commonly planted in butterfly gardens as a nectar source. The plant is used in companion planting for many vegetable crops. Its root secretions are believed to kill nematodes in the soil and it is said to repel harmful insects, such as white flies on tomatoes.
Medicinally, many cultures use infusions from dried leaves or florets. Research also suggests that T. patula essential oil has the ability to be used as residual pesticide against bedbugs. The essential oil is being investigated for antifungal activity, including treatment of candidiasis (thrush) and treating fungal infections in plants.
and also part of the Orange you Glad It's Friday meme.