There is a single species of a rhizomatous perennial, that makes up this genus. It occurs in woodland in Eastern Asia. It has mostly basal, pinnate leaves, and is grown for its poppy like flowers, produced over long periods from late spring to summer. Excellent as woodland or wild garden plant, or for shady pockets, but may spread quickly and smother small plants nearby.
Grow in moist but well drained, moderately fertile, humus rich, neutral to slightly acidic soil in partial to deep shade. Divide in spring.
Prone to slugs and snails.
H. japonica – Wood Poppy – This clump forming perennial from Eastern China, Korea and Japan grows 12″ tall and wide. It produces pinnate, pale green leaves, to 8″ long, consisting of 5 to 7 toothed, ovate or obovate leaflets. From late spring to cup shaped, 4 petalled, deep yellow flowers to 2″ across.