A researched TAFE plant identification study record for Calendula officinalis, commonly called Calendula or Pot Marigold. Despite the shared word “marigold”, it is not a species of Tagetes.

Identification

This upright to spreading herb has branched, often glandular-hairy stems and aromatic, simple leaves that range from lance-shaped to broader forms. Solitary yellow or orange flower heads are composite capitula, with outer ray florets around central disc florets. Cultivars may be single or double. The fruits are especially useful for identification: one head produces differently shaped curved, winged or beaked achenes.

Origin and status

Kew currently treats the western Mediterranean, specifically Spain, as native. Because calendula has been cultivated for centuries and escapes readily, some references describe its exact origin more cautiously. It is now introduced across many temperate regions, including several Australian states.

Cultivation

Sow directly into friable, well-drained soil and maintain even moisture during establishment. Full sun gives the strongest flowering, while light shade is tolerated. Removing spent flower heads extends display; leaving selected heads permits self-sowing. Snails, aphids, whitefly and powdery mildew can occur, so overcrowding and overhead watering late in the day are best avoided.

Use caution

Calendula petals are used as edible garnish in reputable horticultural references, but only correctly identified, pesticide-appropriate material should be used. Ornamental nursery plants must not automatically be assumed food-safe, and traditional medicinal use is not evidence for treating a health condition.