Which types of marigold are effective pest deterrents?

African (Tagetes erecta), dwarf (T. tenuifolia), and French (T. patula) marigolds deter pests by attracting pest-eating beneficial insects such as lacewings, ladybugs, and parasitic wasps.

Specifically, French marigolds are thought to deter root knot nematodes, which live off of and damage plant roots. Popular varieties include:

• Bolero, Bonita mixed;

• Goldie, Gypsy sunshine;

• Petite, Petite Gold, and Petite Harmony;

• Scarlet Sophie, Single Gold;

• Tangerine.

The root knot nematode-resistant varieties will have an "N" on their labels at the nursery, to indicate that they have nematocidal ("nematode killing") properties.