Astilbe are. 'Beauty of Ernst'

Easily grown in average, medium moisture, well-drained soils in part shade to full shade. Prefers moist, humusy, organically rich soils. Soils must not be allowed to dry out. If regularly watered, foliage will usually remain attractive throughout the growing season. A summer compost mulch helps retain soil moisture. Removing faded flower stalks will not prolong bloom but may improve plant appearance, particularly if a ground cover look is desired. On the other hand, many gardeners leave the flower stalks in place after bloom because of the continuing ornamental interest of the dried seed heads. Divide clumps when overcrowding occurs (every 3-4 years).