Caltha palustris
Yellow Marsh Marigold
Ranunculaceae or Buttercup Family
2 to 8 inches tall - yellow
Full sun to part shade
Constantly wet, humus-rich soil
Propagate by seed or division
Photo by Jane Hendrix

Yellow Marsh Marigold is a native of boggy soils in the eastern U.S. For best growth and flowering, keep the soil constantly moist.