Prized for their early spring flowers, Caltha (Marsh Marigold) are rhizomatous herbaceous perennials boasting white or yellow flowers and made up entirely of sepals with numerous stamens. They enjoy a round, mounding habit and grow in clumps in moist to wet, boggy soils. These marginal water plants thrive at the edge or margin of ponds and streams. In cooler climates, they grow from spring through fall, while in warmer climates, they may die back to the ground in summer.