Depending on the species, marigold foliage has a musky, pungent scent, though some varieties have been bred to be scentless.
It is said to deter some common insect pests, as well as nematodes.
 Tagetes species are hence often used in companion planting for tomato, eggplant, chili pepper, tobacco, and potato.
Due to antibacterial thiophenes exuded by the roots, Tagetes should not be planted near any legume crop.
 Some of the perennial species are deer-, rabbit-, rodent- and javalina or peccary-resistant.

T. minuta (khakibush or huacatay), originally from South America, has been used as a source of essential oil for the perfume and industry known as tagette or "marigold oil", and as a flavourant in the food and tobacco industries.
 It is commonly cultivated in South Africa, where the species is also a useful pioneer plant in the reclamation of disturbed land.

The florets of Tagetes erecta are rich in the orange-yellow carotenoid lutein and are used as a food colour (INS number E161b) in the European Union for foods such as pasta, vegetable oil, margarine, mayonnaise, salad dressing, baked goods, confectionery, dairy products, ice cream, yogurt, citrus juice and mustard.
In the United States, however, the powders and extracts are only approved as colorants in poultry feed.

Marigolds are recorded as a food plant for some Lepidoptera caterpillars including the dot moth, and a nectar source for other butterflies.
They are often part of butterfly gardening plantings.
 In the wild, many species are pollinated by beetles.
Depending on the species, marigold foliage has a musky, pungent scent, though some varieties have been bred to be scentless. It is said to deter some common insect pests, as well as nematodes.  Tagetes species are hence often used in companion planting for tomato, eggplant, chili pepper, tobacco, and potato. Due to antibacterial thiophenes exuded by the roots, Tagetes should not be planted near any legume crop.  Some of the perennial species are deer-, rabbit-, rodent- and javalina or peccary-resistant.
T. minuta (khakibush or huacatay), originally from South America, has been used as a source of essential oil for the perfume and industry known as tagette or "marigold oil", and as a flavourant in the food and tobacco industries.  It is commonly cultivated in South Africa, where the species is also a useful pioneer plant in the reclamation of disturbed land.
The florets of Tagetes erecta are rich in the orange-yellow carotenoid lutein and are used as a food colour (INS number E161b) in the European Union for foods such as pasta, vegetable oil, margarine, mayonnaise, salad dressing, baked goods, confectionery, dairy products, ice cream, yogurt, citrus juice and mustard. In the United States, however, the powders and extracts are only approved as colorants in poultry feed.
Marigolds are recorded as a food plant for some Lepidoptera caterpillars including the dot moth, and a nectar source for other butterflies. They are often part of butterfly gardening plantings.  In the wild, many species are pollinated by beetles.
Tagetes