Astilbe are indispensable year-round assets to the shade garden, offering ferny foliage, long-blooming striking flowers, vertical presence, and persistent seed heads in winter. They are hardy from zones 3-9. The flowers vary from upright fans to graceful plumes, and the pink, red, or white flowers attract butterflies. Plants range from six inches high to five feet tall, and many offer striking foliage with bronze or purple tints. Some of the popular species are Astilbe chinensis, A. japonica, and A. simplicifolia.
Choose a partially shaded site protected from the hottest sun. They prefer a loamy soil that is acidic or slightly neutral with good drainage. Plant bare-root plants 4-6 inches deep, with the crown 1-2 inches from the surface, and make the hole twice as wide as the root ball. The soil should be consistently moist but not soggy. If the clumps begin to push out of the soil as they expand, cover with soil. Divide every three or four years.
The soil should be consistently moist but not soggy. Deep watering is better than frequent sprinkling to promote root development. A year-round mulch will help retain moisture.
At planting time, and in subsequent springs, apply a balanced slow-release fertilizer to your astilbes. In a container, consider monthly applications of liquid fertilizer. In fall, amend the soil with compost or soil conditioner to encourage the moist, humus-rich conditions they love.
Pruning is not needed for astilbe. Astilbe makes a nice cut flower for arrangements. Deadheading will not promote extra flowering. However, when leaves turn yellow in fall you can trim them off to clean it as desired, but it’s not strictly necessary. The seedheads can provide attractive winter interest. Divide every three to four years.
Caring For Astilbe in Pots
Choose a site in partial shade with morning sun rather than afternoon sun, which can scorch astilbe. The pot should have good drainage. Take care to keep the pot well-watered, but not soggy. A slow-release fertilizer at planting is helpful, and monthly liquid fertilizer after that is optional. Leave up seedheads to provide winter interest. Divide every three to four years.
Winter Care for Astilbe
Astilbe doesn't need much winter care. Mulch the plants in the colder regions of its hardiness range. Leave up seedheads to feed the birds and provide winter interest.