The marsh marigold is a herbaceous perennial plant of the buttercup family. The plant has dark green hollow stems that grow up to 1 foot (30.5 cm) tall. Its glossy leaves can be either round, heart-shaped or kidney-shaped. The plant is known for its yellow flowers that resemble large buttercups. It flourishes in partial shade in marshy areas and wet woodlands in the temperate regions of the UK, Canada and the northern United States. Marsh marigolds usually produce their large buttercup-like flowers from March until June. In its raw form, the plant is poisonous, but the leaves and roots can be eaten if boiled.
The marsh marigold is also called Kingcups, Bull’s Eyes, Verrucarria, Water Blobs or Marybuds. Shakespeare referred to the plant as the Marybuds. The name Marigold refers to the plant’s use in religious festivals honoring the Virgin Mary in the Middle ages. The official botanical name is Caltha palustris, which is derived from the Greek word for goblet and for the Latin word for marsh. The yellow flowers often cause the plant to be confused with the cowslip, though the flowers are larger than cowslips.
There is some debate as to whether the marsh marigold is a wildflower or a plant worthy of cultivation. While they grow wild in many marshy areas of North America and the UK, they also grow very well in or around water gardens, adding a splash of color with their bright yellow flowers. Because their roots do not penetrate very far into the ground, marsh marigolds also grow well in shallow container water gardens.
The plants can be carefully harvested from local streams or marshes in early spring and transplanted into a water garden. The roots of the plant can also be separated in autumn when the plant is dormant and transplanted into water gardens to bloom in the spring. When transplanting marsh marigolds, the roots should never be allowed to dry out, and the plants should always be placed in very wet, muddy soil. The marsh marigold should also be handled with gloves, as the sap can be irritating to the skin.
Except for the irritating properties of the sap, there are few known medicinal aspects of the marsh marigold. Native Americans were said to make a tincture of the roots to treat sores and colds. The leaves are edible if boiled like spinach, though the raw plant is poisonous. Sometimes the flower buds are pickled in brine like capers.