Caltha palustris

Common name(s): Marsh-Marigold, Kingcup
Blooming time: spring
Blooming colors: yellow, white, double flowering cultivars are also available
Height: 20 to 40 cm
Origin: Asia, Europe, North America
Hardiness zone (USDA): Z6 – up to -18 °C
Family: Ranunculaceae
More infos: all parts of the plant are poisonous