(photo: Kerria Japonica 'Golden Guinea' 5-1-11/My Shady Garden)
The showiest early spring shade shrub I have in the garden is the Kerria japonica. It has beautiful bright yellow flowers that just say “spring. It is a prolific bloomer even in fairly dense shade. It provides a show in late April to mid May with that bright yellow pop when no other bushes have even really leafed out.
My Shady Garden 