Astilbes in the wild are natives of wet meadows and stream sides so take naturally to bog gardens and areas with an adequate supply of moisture. However they are quite suitable for any beds or borders provided they are mulched or water is provided in dry spells.
A well manured area is beneficial to them and they will produce a vigorous plant in these conditions. We have found that it is best to plant them shallow rather than bury the crowns in the ground and also to lift them after a number of years and divide them otherwise they loose their vigour.
The forms of Astilbe simplicifolia and Astilbe chinensis appear to withstand drier soil conditions better then the taller hybrids. These simplicifolia and chinensis forms are dwarf growing (18ins to 30ins) so are ideal for the front of border. Another group, the x crispa hybrids are even more dwarf in form and have bronze foliage.