How to Prune waterside astilbe?
Cut down all stems and leaves before the new spring growth emerges

waterside astilbe · Astilbe rivularis
Grow in moist or boggy soil in dappled shade, or in indirect sun where the soil remains moisture-retentive in summer. Drought intolerant, may be damaged in hot sun. Good for waterside planting. See Astilbe cultivation
Cut down all stems and leaves before the new spring growth emerges