Astilbe Soil Amendment and Summer Shearing

A gardener with 20 astilbes (divided 2 years ago) wanted soil amendment advice for better growth.

Maintenance Routine

• Astilbes like moist, well-drained soil.
• By mid-July, shear to ground if foliage declines from heat.
• Fertilize with slow-release (e.g., Milorganite) after shearing.

Soil Amendment Specifics

• Use finely ground pine bark (nursery standard).
• Mix 40% bark / 60% native soil for shade perennials.
• Add leaves if available.
• At division (every 3–5 years), increase bark to 60%.
• Under heavy tree root competition, add water-holding polymer (Soil Moist).

Bark-based transitions mimic nursery conditions for best establishment.