Kerria japonica Pleniflora

Hardy zones 4 through 9, this native of Japan and China requires part shade and evenly moist well-drained soil. Once established, it can become realtively drought-hardy, but to bloom at its best should not experience drought.

Though it can tolerate more sun, the blossoms will bleech out quickly without some shade. It will thrive in the deepest shade but prefers dappled sunlight to bloom at its mightiest.