Posted: 10/05/2016 at 07:52
Renata, the most important thing for astilbes is MOISTURE.
astilbes will hate being dry. Given moisture they will thrive even in full sun. Ideally partial shade because sunshine brings out the best flowers so a good compromise is called for.
My astilbes are all pretty big growing in a sunny garden but with good deep rich soil.....generously mixed in compost, pelleted chicken manure and dried farmyard manure. I water in hot dry periods.
Of course,,the more sun the drier the soil but there are other factors too...soil, drainage, exposure, etc.
you can plant astilbes so they "show" well now....superb spring foliage and early summer flowers......but allow taller, later perennials to grow up in front to afford some protection from hot sun. For example, aster Frikartii Monch, tall lobelias, anthemis Mrs Buxton, etc.etc., I do the same with hellebores.