Calendula is sometimes called the pot marigold, although it is not in the same family as the common garden marigold. According to the Kansas State University Cooperative Extension, calendula blossoms have been used through the ages to color cheese, butter, broth, rice and other foods, but today are used primarily in skin cream, oil or lotion.
Calendula is a member of the Asteraceae family, along with asters, sunflowers and daisies. It's an herbaceous annual that grows to 15 inches tall. Native to Europe and Africa, the calendula prefers full sun and is moderately drought tolerant.
Calendula flowers are a vibrant yellow and orange. The blooms can be single or double, and they will flower from early summer until the first killing frost, particularly if you deadhead them frequently. The blossoms close each night, reopening in the morning.
Harvest calendula in the morning when the blooms are completely open. If you are harvesting flowers for medicinal properties, avoid ones that have gone to seed, KSU Extension says. The petals will dry quickly, but for complete drying, place the heads in a drying oven.
According to the KSU Extension, clinical studies show that calendula flowers have antimicrobial activity, antiviral activity and wound healing ability. Calendula was also shown to induce the formation of new blood vessels, which is important in wound healing, the Extension says. The flowers typically are turned into gels, ointments, hand cream, shampoos and tea.
Calendula cultivars include "Bon Bon, "Mandarin," "Pacific Beauty, "Coronet," "Geisha Girl," "Kablouna" and "Indian Song," according to the University of Florida Cooperative Extension Service.