Caltha Palustris Plena (Marsh Marigold) Lovely, shiny green foliage with cheerful, double yellow flowers. Marsh Marigold is a lively addition for the borders of your pond, stream bog or other moist areas in your water garden feature. Marsh Marigold grows best in moist, clay soil and blooms in spring and early summer. Grows 12 inches tall in full sun to part shade. Marsh Marigold is an extremely cold tolerant perennial plant and usually the first to bloom in the spring!