Astilbe in August: monthly care

Astilbe's most critical need is consistent moisture. Water regularly from spring through autumn, especially during dry spells, aiming to keep the soil evenly moist but not waterlogged. In hot weather or if planted in sunnier spots, you may need to water two or three times a week. Mulch helps enormously—top up the organic layer each spring to conserve moisture and suppress weeds. In winter, watering can be reduced, but don't let the soil dry out completely, particularly in free-draining soils. Feed astilbe in March or April as new growth begins. Apply a balanced granular fertiliser such as blood, fish and bone or a general-purpose feed (e.g. Growmore) around the base of each plant, following packet rates. Alternatively, use a mulch of well-rotted manure or compost, which feeds and conditions the soil in one go. Avoid high-nitrogen feeds later in the season, as these promote soft growth at the expense of flowers. Astilbe is fully hardy in zones 4a–8b and needs no winter protection in temperate Europe. The crowns die back completely and re-emerge reliably each spring. Every three to four years, consider dividing congested clumps in early spring to maintain vigour—replant divisions immediately and water well. Common pests include slugs and snails, which target emerging shoots in spring; use organic pellets, barriers, or hand-picking. Powdery mildew can occur if the soil dries out or air circulation is poor—maintain moisture and thin overcrowded clumps. Vine weevil larvae occasionally damage roots; look for notched leaf edges and treat the soil if necessary.