Tagetes Minuta is a very good companion plant. Also known as southern cone marigold, stinking roger or black mint, it is a tall upright marigold with small flowers.
Plants are not very resistant to frosts and need to be grown as half hardy annuals. They also need a long growing season, usually flowering too late in the autumn to set seed in Britain. Removing dead flowers before the seed is formed will extend the flowering season.
This plant is widely used in companion planting schemes. Secretions from the roots of growing plants have an insecticidal effect on the soil, effective against nematodes and to some extent against keeled slugs. These secretions are produced about 3 - 4 months after sowing. These root secretions also have a herbicidal effect, inhibiting the growth of certain plants growing nearby. It has been found effective against perennial weeds such as Ranunculus ficaria (Celandine), Aegopodium podagraria Ground elder), Glechoma hederacea (Ground ivy), Agropyron repens (Couch grass) and Convolvulus arvensis (Field bindweed).
An essential oil distilled from the leaves and flowering stems, harvested when the plant is forming seeds, is used as an insect repellent. It is also used in perfumery. Dried plants can be hung indoors as an insect repellent.
Requires a well-drained moderately fertile soil in a sunny position. Grows well in heavy clay soils and in sandy soils.
Sow March in a greenhouse. Only just cover the seed. Germination usually takes place within 2 weeks. When they are large enough to handle, prick the seedlings out into individual pots and plant them out after the last expected frosts.
The dried leaves are used as an aromatic seasoning for soups and vegetables. They give an apple-like flavour. An essential oil obtained from the distilled plant, harvested when in flower, is used as a flavouring in ice cream, baked goods, soft drinks etc.