How to Prune an Astilbe

Astilbe, also known as false spirea and false goat’s beard, is a perennial suitable for part shade but it can handle full sun if the soil remains moist. Astilbe grows in USDA zones 3a to 8b. Its foliage has a fern-like texture growing from clumps that are easy to divide. Thin stems supporting feathery plumes of color in burgundy-red, cream, lilac, coral or pink rise above the foliage of the Astilbe plant in late spring and into July. Astilbe needs little care.

Cut the stems close to the foliage to capture plumes for floral arrangements or to dry for dried floral arrangements and wreaths.

Cut the stems under the plumes (deadheading) after their pastel color has faded if you do not want the flower to go to seed. Plumes left on the plant will turn a rusty-brown, still adding color to the landscape as they produce seeds. The seeds will drop and blow to other locations in the garden to settle for the winter before sprouting in the spring. The self-seeded growth will be short and may not bloom the first year or two.

Cut the plant to the ground in early spring when new green growth is noticed over the brown remains of the prior season. The cuttings can be added to the compost container or disposed of in the trash.

Plant Astilbe

Astilbe enjoys mild weather and a moist soil environment. Soil should drain well and be consistently damp for the best growth potential. The excessive heat of summer makes successful planting difficult at that time of year; results may be better if you wait until fall to plant an astilbe division in the garden bed. While still conforming to the partial shade rule, you can allow the astilbe to have a bit more sun in a different garden location so that it can soak in enough light for root establishment over the winter. The best planting time for seeds is in spring; you can germinate and grow the seedlings in an indoor greenhouse before planting outdoors. Spring and fall heat waves can wreck havoc on sensitive seedlings. As a solution, plant the astilbe near trees and tall shrubs to provide needed shade.