Astilbe, also known as false spirea, has delicate-looking foliage and airy blooms in a host of colors. It is a perennial plant, capable of surviving winters as far north as U.S. Department of Agriculture zone 4. The blooms make attractive and long-lasting additions to both fresh and dried flower arrangements. Astilbe plants require regular trimming to maintain a healthy appearance, especially toward the end of the season, and to keep the plant from overtaking the garden through prolific self-seeding.
Cut astilbe flowers for fresh arrangements when the blooms are approximately halfway open. Make smooth cuts and sever the stems at the appropriate length for the selected vase.
Gather astilbe flowers for dried arrangements just as the blooms begin to open. Again, make cuts as smooth as possible and leave the desired amount of stem in place.
Snip faded blooms off before seeds form, unless you would like the plants to self-seed.
Trim brown and unsightly leaves off level with the soil to keep the plants looking healthy.
Prune winter-damaged foliage back to soil level in late winter or very early spring.