Astilbe japonica are a good choice for shady gardens, where they will grow providing they have rich and moist soils.
They produce fluffy plumes of flowers with mounds of shiny, lacy green leaves and therefore go very well in the semi-shaded spots of flower borders.
They also make very good cut flowers, lasting well in vases.
Make sure they are not in full sun all day, especially the scorching mid-summer type of sun. Part shade is best, trying to avoid the harshest afternoon sun.