K
Kerria japonica 'Pleniflora' (Double Flowered Kerria)
Bright yellow double flowers on large deciduous shrubs to 5 ft. prune to shape. Best in sun.
Kerria japonica picta (Dwarf Japanese Variegated Kerria)
Bright Silvery-green foliage with a splash of cream. Single yellow flowers. To 3 ft. Sun. Zone 7
Knautia macedonica 'Mars Midget' (Red Scabious)
Ruby-red flower heads from Summer to Fall. Compact plants to 10 inches. Best in Sun. Zone 5-7